At the same time, while it may be a legitimate complaint, it's also a bit unrealistic.
Ultimately, they would want as wide of an audience as possible for a new edition.
It saddens me that to a certain extent. While I understand the drive to produce profits, especially in a narrowly profitable enterprise, I have always felt that RPG design should not simply be about increasing quarterlies, but actually refining and improving the design. "Giving the people what they want" is a laudable goal, and I can sympathize with the design team's goal of addressing certain problems, but overhauling the engine every couple of editions leads to two considerable problems:
- really good solutions are never found for the majority of issues; instead, each version has simply a different set of flaws, and
- over time, you end up with competing fanbases, and it will ultimately be impossible to please them all
I suppose it might be possible to make a 5e that echoes a lot of 3e, then a 6e than echoes 4e, but I would consider that a cynical strategy.
From a certain standpoint, it might be nice to continue both families of design, but unfortunately, that takes resources. Further, it puts the games in competition. That is, unfortunately, part of the reason the GSL was created.
While 3e fans can be faulted for at times being irrational in their criticisms, I think it must be admitted that they are justifiably angry that WotC has actually attempted to stamp out support for their chosen edition. While I can believe someone like Mearls might oppose something like that, it's just not fair to pretend that didn't happen and that an edition war of sorts is not going on.
Fans do face pressure to update; the new digital tools support the new edition, only the new edition is being supported, and sufficient compatibility issues were introduced that many miniatures and sourcebooks are now incompatible with the new D&D world. Further, the third party publishers have been squeezed, in many cases being asked to abandon 3e in order to support 4e with a particular product line. Third edition is under attack.