I don't agree with this part in particular. I don't think complexity is a requirement for a game's success, but there are absolutely players who rave about complexity. I work for a mobile game company, for example, and my Boss and I both are into mobile gacha games like Genshin and Star Rail. He's particularly interested in the upcoming Wuthering Waves specifically because its combat is more technical and complex than Genshin's which is not entirely simple, but doesn't really feature many technical aspects to its combat largely because being on Mobile first means the controls make it difficult to perform at a technical level. Wuthering Waves is not going to be a mobile game and is emphasizing its combat more, which is a selling point to that game over its biggest competitor. This is anecdotal of course, but there are many games where the complexity and depth are a selling point for people.
Now, simple games can also be very successful, but I think something worth noting is a lot of games that are simple, are simple on the surface, yet have an ocean of depth beneath the surface that players can optionally engage in. Super Smash Bros for example is, on the surface, a casual party fighter game, but also has an entire community of competitive players who will break down details as small and seemingly minute as frame data. Super Mario 64, a classic masterpiece, is a simple game to play with lots of ways to engage with its platforming at a far more technical level. Look at any speedrun of the game, and you can see that in action. Even Tetris had a layer of optional complexity that drastically impacts how a player builds and clears their map: T-spinning.
FFXIV on the other hand was already a simple game. What they have been doing is not making the game more simple, but actively stifling the optional depth that used to exist within its job design. In that regard, I would argue FFXIV is gradually approaching Balan Wonderworld with each expansion, a game full of power ups that are all basically the same and a control scheme where every button does the same thing--A game where depth is stifled and you are forced to take the game at face value and nothing further.
Bushnell's Law: The best video games are the ones that are easy to play but difficult to master. FFXIV stands in opposition to this by being a game that has always been easy to play, but seems desperate to force it to be easy to master as well. It's like with this segment of Misshapen Chair's more recent FFXIV job design video...
"Because every single little tiny thing that requires any modicum of additional effort or is slightly outside of the exact scenario that they practice is frustrating."
In his video, he's referring to the types of players who want to be the best at the game, but have no interest in putting in any amount of effort to become the best. But that does seem to be how the design team are approaching changes. Anything that even sounds like it has the tiniest amount of complexity is something that needs to be purged, or sanded down into oblivion.