Good stuff, but I think also misses the point

 

This is a really interesting analysis, and there's a lot of off-hand gems in there too, like comparison of setting material historically compared to other stuff. But I also think that he misses the point because he makes an unwarranted assumption and doesn't realize that that's really just an unjustified assumption; he thinks that it's a foundation. This is how people get the wrong null hypothesis in their analysis.

What it assumes is the following, in a kind of nested order:

1) D&D is about combat. It was clearly optimized to run combat, and it was the only thing that they thought about in the design of 4e, and they thought 3.5 was all about that too.

Oisin in "friendly mode"

2) D&D players are split into casual players who just want to hang out with their friends and pretend to be an elf, and the people who really want to dig into the rules and be munchkins, optimizers, power-gamers and tacticians. There's no acknowledgement of the roleplaying side of the game, and in spite of everything that he observed, he still doesn't seem to acknowledge or recognize this cohort. My own rough anecdotal evidence is that if the power-gamers/optimizers/munchkins are 20% (his number, near the end), then half of the remaining 80% aren't just casual "hang out with my friends" player, they just prioritize things that are completely different, and are apparently off of his radar entirely.

3) Which is kind of shocking, given that that cohort in theory led the 90s revolution in gaming, spear-headed the whole Storyteller slash White Wolf game model, and was even hugely influential in the development of 2e products overall. Did he think that they just all went away during the 90s or something? For this group of people, not looking at your character sheet and just describing what your character does in natural language and making natural assumptions (as opposed to picking a power to use from your sheet) isn't an expression of casual interest in the game; it's the whole way that you're supposed to play! That's the whole point! That's called immersion and role-playing! Isn't that the whole trad model, really? Y'know, the mainstream mode of play through much of the 80s and 90s, and beyond, in addition to the mode of play of most other games that aren't D&D much more explicitly?

4) This mode of play isn't just some kind of anti-D&D mode of play, or something that died out in the year 2000. Sure, sure... d20 could be used as an optimization munchkin's favorite game within a game, but for people who never cared to play that way, it also offered all kinds of role-playing options. Picking a prestige class or feat or the highly granular skill selection system wasn't just about optimizing damage in combat; it allowed you to roleplay with actual mechanical teeth to your roleplaying. You'd pick stuff that sounded interesting to you from a roleplaying perspective, and you'd actually have mechanical justification for it; it wasn't just "because I said so." It honestly didn't occur to me for years that any d20 game would have munchkin problems, although I now hear about it as if that was the sole takeaway of that family of games.

It's interesting that they found out that they were building 4e for an audience that they thought was the audience, but that it was a mirage, but that he still doesn't understand the immersion/roleplaying cohort at all, or even understand that it even exists! And, he makes the assumption that people who didn't want to play 4e had to move to Pathfinder... when in my experience that wasn't the only option at all. My group kept playing 3.5 until at least 2016-7 or so, and if we hadn't broken up due to relocations and all kinds of other things, we would probably still be playing it literally today. Since 3.5 books never went down in price in the used market, I presume that a very large cohort was still playing; probably at least the same order of magnitude, if not literally the same numbers, as those who played 4e or Pathfinder respectively. And, of course, this was the first big growth of the OSR as an alternative to both. I think 4e didn't lead to a bifurcation of the market, it led to an unprecedented "multifurcation" of the market, where multiple forks were at least in the same order of magnitude if not really the same size. 

D&D is successful as a big tent when it can actually accommodate multiple styles of play successfully. I never had much interest in playing in what he seems to assume is the way that "serious" players play, yet my participation in the hobby is hardly casual. When it forgets about entire cohorts of the player base, or mistakes a cohort for the whole, is when it fails to successfully bit tent. As much as I don't really like 5e all that much, I can certainly recognize that it's a successful big tent, for many of the same reasons that d20 was a successful big tent. 

Although I also find it curious that he says that 4e's development started so soon after the release of 3.5 because 3.5 didn't hit the sales numbers that they wanted it to. Probably because it was 3.5. Everyone more or less knew what to expect, because 3e was the big watershed release; 3.5 was an iteration, and it wasn't strictly speaking necessary to buy it. I was salty about the release of 3.5 so soon after 3e, I didn't see the need for it, and honestly I didn't buy the core books until way, way late. I only bought the DMG and PHB in the last two years, in fact, long after I'd stopped playing 3.5. I bought plenty of other 3.5 books, but getting a revised version of a book that I already had? No, thanks. I either adapted what I already had or used the SRD.