Why am I seeing a lot of "I don't need this" or "I don't need that"?
If you want to go that route then you are definitely not Wizards' kind of customer because technically you don't "need" to buy a new edition because the previous ones still work just fine.
The catch is, WotC can't just give up on a chunk of the audience like that. If they're releasing product that doesn't excite a large percentage then that's money they're losing. They're throwing away sales. When they release an accessory, they want everyone to go "I
need that." One of the best ways to do that is to make accessories and new books rarer, and thus more valuable through scarcity. Rather than "ho hum, another book" they want people going "OMFG another book!"
Just like how no one cares when Stephen King or John Grisham releases a new book but everyone loses their s***** when Rowlings or Martin releases a new book.
Plus, releasing lots of books has proven detrimental to the hobby. Which impacts everyone, not just those buying the books. As suddenly the edition cycles over again and it becomes harder to buy the older books or get new people into the hobby.
This isn't about needing anything so I'm not sure it seems to creep into several posters remarks. This is about the many gamers out there who do want more product. Also, could we please stop with the disingenuous comments about bloat and mountains of books? It's like some of you can't differentiate the now release schedule and the one from that last two editions. Nobody here has said they want mountains of books. I certainly haven't and it seems that if you want more than what is currently planned then you suddenly must be in the "wants tons of books" category of people.
How many books do you want then? The game has been out for 10 months at best and there are six hardcover books and a boxed set. That's more than a book every other month. And we're going to get yet another book on month 13 (August) and maybe even two.
Do we *need* monthly books? Two books every three months?
Or do books not count if they're not player accessories? Is it not that WotC isn't releasing books but that they're not releasing player-focused splatbooks with waves of generic and forgettable options?
The catch is we're talking about the "long term". You put that term in the title of the thread. And the long term becomes the now very quickly.
Pathfinder hasn't released many hardcover books. They were averaging three a year for most of the edition's lifecycle.
They've only really been publishing Pathfinder for five years: August 2009 to now. What does a Pathfinder collection look like:

I don't know about you, but that looks like a
mountain of books. And it's missing five hardcovers (the most recent two, Rise of the Runelords, and two that I forgot because they were on the wrong shelf).
Even if D&D only releases the two adventures and one accessory or campaign setting book every year, the pile of books with be just as high as that pile after the same length of time. It adds up super fast!
And it's needless. It's so needless. Let's look at the rest of my D&D shelf:

I've circled a few editions. 1st Edition is in red, 2nd Edition is in blue, and 3rd Edition is in green.
Now I'll highlight the books I actually used during my games. The products where more than a single page was used. Books where a single feat or magic item were used don't count.

Most of those books could have been novels or GURPs for all the play they saw at my table.
Now, some tables might have a higher percentage of use, but I guarantee there were some options no one ever used. There were some spells or Prestige Classes or feats that not a single player every took in the fifteen years the edition was on shelves. Because they just weren't good. There were so many bad options created because a quota needed to be filled.
That's bad. We shouldn't have bad options. Nothing should be created that people honestly don't think is a valid and reasonable option for somebody. But the more content is created - even if just a book every six months - the less and less chance an option will be chosen. The less and less valuable the books become. The more it just becomes a wasted purchase.