I think a whole lotta of this can just be laid the feet of edition change. One need only look at the change from 1e to 2e, which compared to 2e to 3e or 3e to 4e is hardly a change at all in terms of rules. Still, a whole lotta folks didn't make the switch, and a good many harbored resentment about it.
See, I read people saying this about the 1e-2e transition, but I just don't recall it (granted we didn't have the webs to spread our disgruntlement, but there were still conventions I attended) I don't recall the 1e-2e jump being advertised or received as some tremendous update/shift in the rules...more a clarification and badly needed editing/representation. I suppose there were those who didn't change, but you could still basically run the two together...(at least plenty of folks around me did.)
Similarly, by the time 3e came out, most people around me were either dragging themselves with increasing resentment through 2e campaigns that were heavily houseruled or had switched to another system/game or had stopped ttrpg gaming. For a large number of younger people, Fantasy gaming meant computer games and Magic:the Gathering. The coincidental(?) release of 3e and the Invasion block resuscitateda lot of D&D in my circles.
Neither of those (and I was patrolling the conventions, forums, and lists by the 3e release) had anything near the widespread vitriolic rejection that 4e engendered (fairly or unfairly). Yes, there were occasional objectors and objections, but nothing near the wholesale defections represented by Pathfinder and the 3.x folks (let alone the OSR folks, who I think are honestly a relatively small minority, despite my participation in an OSR group right now.)
IMO,
time (in addition to WotC's PR incompetence) is the critical factor. I think that we get bored with our rules and books after a while. We squeeze whatever good easy fun out of them that we can...and then we start to tire of them. The trouble is that this boredom takes far longer to set in (several years at least) than the "new edition" turnaround time that WotC needs to keep D&D a viable business on an ongoing basis (apparently less than 5 years). This puts WotC in the awkward position of pooh-poohing a product that they just sold you a year or two ago, or "updating" rules that you didn't think were an issue.* We just aren't bored with the system by the time a new edition is coming out.
Personally, I suspect that 5e may be the "farewell" edition. That WotC puts it out, and then only meagerly supports for a few years before closing the department. Provided someone remembers to check in 10 years, they might whip out a 6e or something to take advantage of that boredom. I would honestly suspect that to be more along the lines of the 1e-2e "jump", but that's stretching my prognosticating powers. Alternatively, if they find a way to hook us monthly (and if the experience is close enough to tabletop, I might be interested) the game could stay vital for much longer.
Of course, I could be wrong. Making predictions is hard, especially about the future.
*Additional Evidence: Both 3.5 and 4e contain many design elements/motifs that make it easier (theoretically) to play online, and WotC has several times stated, leaked, bragged, or over-confidently announced their desire to create an online D&D experience to mimic the tabletop....thus turning an occasional $30 purchaser into a $5/month subscriber. Why they seem to have soooo much trouble with this is a mystery that I, as an occasional software author and consultant, cannot fathom.