Hussar
Legend
Where you go wrong is in assuming that 30 million = identical sales. It doesn't. Of those 30 million 5e players, only DMs really need the MM and DMG. Some players will buy them, but you only need one book each per 4-5 players. With all the splat books in 3e, players had a lot more to spend money on.
That's really missing the point. It IS identical value of sales. The difference being that 5e is making those sales with 11 products instead of investing hundreds of thousands of dollars on splats.
If the supplements make no money and have no real impact on core sales, why would they make them? Where's the upside?
Ahh reread this. The market is 30 million DOLLARS not players. In its wildest dream DND has never come close to 30 million current players.