Your core book (or books) are going to sell more than your expansion books. Some people are going to buy expansion books by themselves, but these people are ridiculously in the minority. Normally you can expect all the players to buy the main core book, a big chunk of the players to buy any secondary core books, and some fraction of the player base to buy expansion books. Stuff like Adventures barely pays for itself, but you're mostly using those to advertise the corebook honestly.
I regard the 4e strategy of "Everything is Core" to have been a failure. I feel that I am totally justified in this assessment, because WotC regarded it as a failure and reclassified all the expansion books as being "D&D Rules Supplements." Everything is Core is a dead concept. And I suspect that it scared people away from the line. People saw a list of ten "core" books, decided that they didn't have 300 dollars to drop all at once, and just didn't. Nevertheless, "core" books sell better than "supplements" so you're going to want to print some of them. But spaced out, so that people who feel that they "must" buy every core book don't feel wallet shock and abandon your game.
For every book you make, you're going to be balancing two things: Number of Interested Customers, and Value per Customer. That is an important distinction. Every player who feels that there is something of value to them will consider buying the book, but in that consideration goes a mental equation of how much of the book interests them against the cost. This means that a book like the Complete Divine may well outsell a book like the Complete Adventurer - because a book that has a lot of material for a small part of the fan base may sell to a large percentage of those people, while a book that sells to a small percentage of a larger swathe of the fanbase may add up to a smaller group. Critically we see this with Shadowrun books like Feral Cities and Corporate Enclaves. Since each of those books had a bunch of unconnected cities in them, the chances of more than a tiny part of each book being useful to any game group was extremely slim. And while lots of people had their interests somewhat piqued - the actual number of people who paid for copies was very small.
An Edition of Shadowrun
Shadowrun is not like Dungeons and Dragons or World of Darkness, in that it claims to be complete out of a single Core Book. This helps considerably with wallet shock for new players, in that they are grabbing a single book. It may hurt the sales of later core books some, but I don't really see any evidence of that.
Supplemental Core Books Shadowrun has a long and successful history with releasing a "core" book for each broad type of enhancement: magic, biotechnology, gear, and matrix. This is a successful model, and only needs to be adjusted later in the game's cycle by adding additional core books to the mix.
Location Supplements Location supplements have a spotty history. Some of them, like Seattle 2072 and Tir Tairngire: Land of Promise did well despite me thinking they were dumb. But a lot of them tanked hard. I'm not sure if the Germany Sourcebook sold through even today. Location surveys like Shadows of Asia and Shadows of Europe worked, but location surveys like Runner Havens and Feral Cities were expensive failures. I think the key is that a location book should talk about gong between every area in it. So surveys of locations that are next to each other have inherently more traction than those that don't. Seattle sold when it was the core setting, and adjacent countries like Tir Tairngire sold for that reason.
Event Books People like the Shadowrun metaplot. If it advances too fast, people complain, but stuff like System Failure gets high marks and reasonable sales. I believe that even one per year is probably too fast.
Concept Supplements Shadowrun really lends itself to books that are about a certain kind of crime or shadowrunner. Cyberpirates, Shadowbeat, we love it.
Adventures The adventures sell poorly and are only needed for cons and introductions. Frankly the Missions model is pretty decent. They need to be restructured so that people are paid royalties instead of flat fees for Missions, and then the whole Mission Team can be outsourced. They should also be produced continuously, to the point that I'm not going to bother putting them on the schedule.
The First Year
- Shadowrun 5: The Core Book. The big cheese. The money maker. The thing that everything
- Sixh World Almanac An overview of each of the countries in the sixth world. With maps.
- Ghost Hunters The first Event book. Restore the Treaty of Denver. Kill Ghostwalker. Not in a bullshit "no body" way - fucking murder his ass. That'll wake people up. The book presents Ghostwaker's bad ass stats, and presents some options for the PCs participating in the international conspiracy to do it, up to and including helping to pull the trigger themselves.
- The Setting Sun The first location book. Vancouver, Seattle, Portland, San Franciso, LA, and San Diego. Has a section on the Salish-Sidhe, the UCAS, Tir Tairngire, the CFS, the PCC, an Aztlan. Discussion on smuggling things and hostilities between those countries.
- War! The first Concept Supplement. It's about Mercenaries.
- Destroying News The second Concept Supplement. It's about news, information warfare, and public relations.
- Modern Thaumaturgy The first bonus Core book. The Magic book.
- Human Resources A Concept Supplement - human trafficking, slavery, cannibals, and insect spirits.
- Rising Suns The second Location book. Vladivostok, Pyongyang. Tokyo, Hong Kong, Ho Chi Minh, Singapore. Needless to say, has a section on the New Soviet, United Korea, Imperial Nippon, the Canton Confederation, Dai Viet, and um... Singapore. Talks a lot about corporations, in addition to international smuggling. Evo, Shiawase, Renraku, Mitsuhama, and Wuxing get top billing.
- Silk Road A Concept Supplement - drug smuggling, dealing, and drug wars.
- A New You The Second bonus core book - augmentations.
- New Horizons The second Event Book.
- Arsenal Bonus Core Book - gear.
- The Black Flag A Concept Supplement - Piracy.
- Extraterritorial The third "Location" book - it's all about Corporate territory.
- Virtual Realities Bonus Core Book - Matrix.
- Shadowrun... in Space! A location book. In space. So you talk about the Mars base, the Moon Base, and four of your favorite space stations. Lots of discussions about how you get from place to place in space with Shadowrun's future tech.
- Blood Money A Concept Book - Assassins and Bodyguards.
- Bumps in the Night Bonus Core Book - Beastiary.
- Eating Dust Concept Book - Smugglers and vehicle thives. Selling Contraband.
- Plastisteel Curtains A Location Book: Pick three Western and 3 Eastern European cities. I'm fond of Paris, Frankfurt, and Naples vs. Krakow, Prague, and Bucharest, but your mileage may vary.
- Earth Rise An Event Book.
- The Monofilament Edge Bonus Core Book. Focuses on crazy advances in magic and technology.
- Cloak and Cyberspurs Concept Book - Spies.
- Shadows of Africa A location Book focusing on Africa.
- Runner's Companion Bonus Core Book. Bullshit player options, like being one of those four armed dudes whose name translates to "prostitute."
- Heavy Plastic Bonus Core Book - mostly vehicles, building materials, explosives, and military equipment.
- Rival Houses Concept Book - Criminal Syndicates
- Transatlantical Location Book - London, Dublin, Boston, New York, Nuuk, Atlanta. GB, Tir na nOg, UCAS, Transpolar Aleut, and CAS.
- Bug Hunt Concept Book - bounty hunters and monster killers.