When D&D 3.0 came out, I thought it was great fun and a great improvement. It wasn't actually my preferred style of RPG - I like more freeform and fewer crunchy bits - but it made sense, it was recognizably D&D, it had some support for non-combat activities in the feats and skills system and occasionally in the class abilities, and it was a distinct and clear improvement. All in all, it was a better system than I was expecting, and I really liked the way they managed to keep classes but not limit you to classes.
Furthermore, while old adventures would require a lot of conversion and old settings would require some, they could be converted, complete with characters. Take the old character classes, pick new classes for cross-class characters, pick skills and feats. I still love Planescape and Spelljammer from 2nd edition and I've never even played them, so I thought this was a plus. For settings, were I GMing, I'd even be willing to improvise a conversion -- have some stock characters in case of combat, but combat shouldn't happen that often, make notes as to skills you select for the NPCs as you go along, and play.
So for D&D 3.0, I had some discretionary income, and I went out and I bought a whole bunch of books.
When D&D 3.5 came out, it felt like the publisher was trying to turn a whole lot of errata into a new edition. Yes, it was better. But it didn't feel like D&D 3.5, more like D&D 3.1, and while I did buy the new edition I resented doing so. Still, the SRD was available and the product was an improvement, so I didn't resent it much. It was just a monetary complaint; D&D 3.5 had all the virtues of D&D 3.0 and slightly fewer flaws.
Then oodles of supplements came out for 3.5. The number of supplements exceeded what I wanted to spend on buying role-playing games - especially for one system that wasn't even my favorite - so I picked and chose what to buy. I had a friend who bought almost all of them, at least one more who bought more than I did, I could afford the ones I really wanted -- that was fine. I was unhappy about the power creep, however: most of the prestige classes seemed to be clearly better than the basic classes, and the later supplements seemed to have some unbalanced one. Still, there were no problems that couldn't be solved by a DM saying no as needed, and a lot of the material was cool. I was fine with it.
Then D&D 4 came out. My reaction at the time as "that's interesting, and it's different" and I bought the core rulebooks. I only bought a couple of supplements, though, and even though I'm in a campaign I haven't replaced my missing-somewhere copy of of the Player's Handbook.
I actually like D&D 4th edition and in many respects think it's a superior product to D&D 3, even D&D 3.5. It's more streamlined, better balanced, and so on. The skill challenges give explicit support for noncombat activities, and the skills system sees to it that everyone will have some noncombat skills.
However, in many respects D&D 4th is a streamlined wargaming system with role-playing rules. Imagine playing D&D 3rd without a map. It's a problem - you have to figure out who is affected by which spells, whether there are clusters of enemies for some feats, flanking bonuses, and the like. But it's not impossible. The GM can figure out the rough positions of the monsters, the players can make assumptions, the GM can let the players do a certain amount of scene-setting, and so on.
Now imagine playing D&D 4th without a map. Well, it's not impossible, because you can do pretty much anything without a map if you ignore enough rules, but all the above difficulties apply, and more. The whole mechanic of sliding and shifting becomes either unusable or subject to whim. Various race and class specific abilities (e.g. the elf's ability to ignore difficult terrain, the wizard ability which pushes back nearby enemies, etc.) are less effective or far less objective.
It's not that D&D 4th isn't at least as good as D&D 3rd in its chosen niche of combat-with-map and simple noncombat challenges. I think it's better in both respects. But D&D 3rd is better on the occasions you want to keep playing when you need to fill the table with dinner. The skill challenges of D&D 4th can easily be imported into D&D 3rd as soon as you see them, so that's more or less a wash.
Also, I think the lack of backwards compatibility hurt D&D 4th than it looked like at the time. Not only were all the recent 3rd edition purchases totally incompatible with the new edition, but the myriad D&D 2nd edition products were now incompatible instead of semi-compatible. I was expecting it, and my 3rd edition game (thank you for a wonderful game, crash_mccormick) had ended, so I wasn't upset, and I don't think it influenced my decision to buy only a few supplements. But I can certainly see why people who were in a game and having issues with the rules might go to Pathfinder for a few fixes rather than go to D&D 4th for a totally different game.
Also, if the new system isn't compatible with old material, why would you purchase and play D&D 4th edition instead of Pathfinder, another of the D&D 3rd edition variants, or any one of the many other role-playing games out there? Name recognition matters, and so do economies of scale, but the D&D 3rd edition had those too. And the D&D 3rd edition variants (Pathfinder, etc.) are mostly compatible with the old D&D 3rd edition books and each other and semi-compatible with the wealth of D&D 2nd edition books.
So Hasbro put itself in a position where its legacy materials helped its competitors' products more than they helped D&D 4th edition. No wonder Pathfinder became a major rival to D&D 4th edition.
Cross-posted to ecreegan.dreamwidth.org at http://ecreegan.dreamwidth.org/4390.htm