I'm just starting a new campaign with Dragon Heist.
Now, for a bit of background, this is the first official D&D adventure path I've run since... errr... Savage Tides back in the tail end of 3e. Wow, it's been that long. And, something that REALLY slapped me in the face is how different things look now than then.
WotC's AP's aren't really just AP's anymore. They are a core book for an entire line. Looking at DM's Guild, there are more than a dozen supplements, all high quality, professional stuff, just for a 5 level module. O.O Dragon Heist has been out for what, six months? Thereabouts. And we already have enough material there that I could, if I wanted to, stretch that single module to a pretty lengthy campaign.
This is, IME, unprecedented. The modules, whether AP's or not, in the past were all fire and forget. You bought Return to the Temple of Elemental Evil, maybe picked up a web enhancement and that was it. There wasn't a long tail of products that you could buy for a given module.
It's a really different market. Each module now has this tail - extra modules, figures, maps packs, whatever - of products that keep that module floating. While it's remarkable how well the core books are selling, what really, really blows me away is things like, say, Rise of Tiamat - a module that wasn't exactly a rousing success as far as gamers were concerned- is STILL 5000 (ish) of all books on Amazon.
Think about that for a moment. A four year old MODULE is selling that well. That's unheard of. Four years after a module is released into the wild, the normal life cycle would be recycle bins at gaming stores. And that's the WORST WotC offering as far as Amazon rank goes. Good grief, Hoard of the Dragon Queen is just shy of breaking the top 1000.
The new market for WotC is a very different place. Each product that WotC bangs out isn't a stand alone thing. Each one is an entire line unto itself that feeds into the main line. I mean, think about it. How many supplements were there for any module previously? Modules with their own miniatures? You might have gotten some fiction books, I suppose, but, even then, that was pretty rare outside of Dragonlance. It's not like the Forgotten Realms novels followed modules.
But, all of this creates such a unique position for WotC and its products. You're not going to see a "Complete" line anymore where each book is largely fire and forget with a six month sales window and then fading into obscurity. No, what we're going to see is things like Ravnica where you have WotC bringing out the main product and then everyone else feeding into that main product.
It's a really interesting way to combat fragmentation of the fanbase. If the 3pp are directly latching onto WotC products the way they are, it keeps everyone much closer together and allows a LOT more cross pollination.