Vox Populi Forum
The online SRD's are pretty complete and easier to find things.
And Wizards put out a free PDF in the early days.
There's not much more in the Player's Hand Book that you "must" have. They added a few bits and pieces and then added 3 or 4 more books each with a bit of this and that. At level 3, the classes specialize and you get to choose 1 of 3 paths. Each of the expansion books gives you another choice. (You can have the pyrate Rogue if you but the Sword Coast book for example.)
The Ref book is, as it was, a place to look up loot but you really only need one of those in the group. There are some interesting bits in the DMG but nothing you must have. (First edition remains superior there.
Xanthar's put some stuff back in that was removed that is useful random stuff.)
The MM is just a list of monsters and their stat blocks. Again, all on line and easy enough to make them up if needed.
Does it matter if the Troll is 10 dice or 12 dice? Again, one copy will do.
The miniatures were a good thing. Are they still selling those? I see the boxes for the various campaigns but there are a bit pricey in my eyes. (The random item thingy doesn't work as well for miniatures as cards.) I would by 20 orcs if I could do so (and I didn't already have 50 in lead and ready to go.)
Everyone needs set of dice and now ... a dice tower ... that still makes me laugh.
It would have been nice if, like EPT, the 3 books included a campaign setting and some religion pantheon information. What is in the book is not much. Even the factions which were touted at GenCon get barely a mention. Zhentarim anyone?
Magic was great for the Friendly Local Game Stores (FLGS) because it kept the dollars moving. The Dice Master was a short blip but nothing replaced the fury like the cards.
There are a lot of neat board games but once you own them, there isn't much add on.
Otherwise, I can't speak to the economics other than it must be tough.