It is repeating the mistakes of the past, but in a different sense than you mean it.
WotC is in a totally different failure mode than TSR was at the end of its life. WotC's current failure mode is a result not of repeating the mistakes of the past, but an attempt to replicate its past successes. In terms of aphorism, the one most relevant here is 'fighting past wars'.
In the early 90's, TSR had suffered for a dearth of good writing and produced a lot of inexcusable trash. But by the mid to late 90's, TSR actually had a core of good writers - the same writers that would later on go on to make 3e a success - and product quality in terms of writing at or around the 30th anniversary mark was actually quite high.
But what was killing D&D at the time was a clunky rules set that hadn't really integrated any of the lessons learned over the prior 30 years and still felt like it came out of the 1970's. Most people, myself included, had come to feel that the rules set was just irredeemably bad and ill suited to running a modern immersive game. No one was really paying much attention to D&D because it seemed like a game of the past and even there good content wasn't attracting much GM attention except from the diehards that wouldn't run anything else.
3E therefore came as a revolution - proof that the core rules of D&D were still solid and relevant and could be the basis of a mature fantasy game. The core D20 mechanic, hit points, classes, and the rest were redeemed, and there was a lot of reevaluation of the D&D concept by GMs like me that were finding high realism, lethality and grit and so forth not the be all end all of RPing. GMs came back to the game.
But WotC had made a critical mistake for all of its success. Knowing that the problem was the rules set, and knowing that a portion of what killed 2e/TSR was its over focus on creating IP, WotC decided to largely forgo creating new IP for the 3e brand. Instead, it bet everything on being a crunch factory and choose to largely outsource fluff production on the grounds that crunch was higher profit. This ultimately led to a focus on player centric fluff and a player centric rules set because there was more immediate bang for the buck in selling books to players than GMs. Meanwhile, fluff - adventures, settings, etc. - was largely in the hands of third parties.
4e and now D&DN represent the thinking of a company that believes its flagging sales are the result of a rules set that hasn't evolved with the times, and that the core selling point of a gaming company is its system. This is a company that believes that reason people play a game or don't play a game and most importantly do or don't buy a game is the quality of the rules set, and after all that is was to a large extent true.... in 1998.
But this isn't 1998. It's fighting the wrong war, and in doing so its killing its own brand, Balkanizing the community into separate non-conversing communities in a way far exceeds the isolation caused by 2e's diversification of setting and greatly reducing the inherent appeal of the D&D rules set in the process.
Meanwhile, if you look at what it's competitors at Pazio an Monte Cook Games are doing you'll see that Pazio has built its empire on exactly the opposite approach from WotC post the introduction of 3e. Instead of building a player centered game, their core business identity is in fluff - the adventure paths. And their rules/crunch production is at least as heavily geared to producing GM tools as it is to providing player options. Monte meanwhile proves his real genious by completely understanding where his previous work was failing, and for Numenera is engaged in some of the most novel and expansive IP generation related to a PnP game launch I've ever seen.
WotC is about as relevant as the dodo bird, still thinking that if they just found the magic rules set everyone would be playing their game again.
