I hear what you're saying, and I think this is a thoughtful post, but I don't think nostalgia plays as big a role as you think. All of the people I know who still play an older edition just love it. They don't break anything down and talk about "design" the way modern game whizzes do. They sincerely believe that the older editions had the best design, simply because they were the most fun in their personal opinion. The people I know who still use THAC0, for example, won't hear of anything unintuitive about it. They aren't doing it for nostalgia. It never stopped being part of their passion.
You kinda just defined nostalgia, with those last three sentences.
Since joining the online gamer community, I’ve come to understand why a lot of traditional D&Disms are the way they are, and to see the advantages of some of the quirks which I had originally dismissed as nonsense. Like xp for gold, for example. It makes no sense from an in-world perspective, and it doesn’t fit the heroic-quest play style that dominates modern modules and APs. But for the play style that Gary and Dave originally conceived of D&D with, xp for gold makes perfect sense, and it’s a demonstrably better motivator than xp for victory or xp for quest completion.
But there are some things which just don’t stack up to modern improvements, despite now understanding how they came about, and thac0 typifies this kind of thing. I understand that it’s an improvement on the look-up charts that preceded it, which makes it a great innovation for its time. But I’ve never heard anyone come up with a positive contrast to the attack-bonus system. Typically thac0 is defended with ‘It’s not that hard’ and ‘It’s better than the zillion modifiers that come with modern D&D.’ The first defense, while true, doesn’t change the fact that the attack-bonus system is even easier. While thac0 itself isn’t a game-ending hassle, it typifies a system chalk full of odd subsystems; higher numbers being better than lower numbers is simply more intuitive than vice versa, and addition is easier than subtraction. The second defense is a subjective statement that conflates two separate game issues; the attack-bonus system can (and I believe has) been back-ported into retroclones without ‘bonus-bloat’ to create the best of both worlds, and thac0 could theoretically be forward-ported into a modern system to combine the worst of both worlds.
When someone says “I like prior edition or retroclone X overall better than 4e, despite whatever flaws it may have in contrast to whatever features 4e may have,” I take them at their word. But when someone focusses on 4e flaws — often entirely subjective flaws/features, by gamers who haven't even played 4e -- while denying or downplaying the flaws of other editions, I can’t help but think
nostalgia! And I've heard and saw a lot of that during the past seven years. I still do, once on a forum completely unrelated to gaming! So while it’s impossible to quantify how big a role nostalgia plays in edition wars and the short 4e lifespan, I don’t think that Stacie is overstating its influence on gamers.