They might have the numbers, but they don't necessarily take the context behind it. They said they considered Alexander normal to be a "success" because of the clear rates (or at the very least, Yoshi-p is extremely satisified by it and they won't drop the model). But why is it a success? Why is the clear rate so high? Would they consider 3.1's MSQ to be a success with it's current clear rates?
I personally would have preferred normal mode to be akin to FCoB because that's something that allows for a natural nerf to it with echo to open it up to the "non-challenge seekers", along side with the numerous other content (debatable if it's good or not, which is a different discussion) that they already have. With the setup we have now, you have pepole that don't care for a challenge, the people that want to raid, and the people that want to hardcore raid. A good chunk of the playerbase is in the middle as well, but the current set up of the content does not cater to that with how tuned savage is.
This would have been the ideal setup. The barriers eventually get tuned down in the form of progressive gearing (espesically in a vertical progression), and there's no need to pre-emptively plan for content that opens up to players that do not have a interest in raiding or commitment.
Look at the other perspective, the people that want to do things like raid only have savage mode to look toward. It's tune up so high that even ilvl supplementation doesn't help, and you don't nessescarly want to nerf savage mode if it's intent is that it's supposed to be hard. They're seeking a challenge, but it's not nessescarly the challenge they want, but this only became evident (and in large strides no less) with Alexander Savage in comparison to FCoB.
People already min/max in accordance to the substats which have very small influence on actual gameplay. On top of that, players had already excluded certain jobs or players whom have not cleared the content from doing content. Player (ir)responsibility should not be a reason to not implement something, honestly.
Again, people already do this in regards to anima. I personally have been burned out and bored long before anima came, but at the same time, I have not cleared A4s to fully slot my main. We've actually been on A3s for months now, and while its technically "something to do", it doesn't change the fact that the burnout still occurs for other reasons.
The problem comes is that it delivered very little in regards to what an expansion is supposed to do, as well as the groundwork it lays out. No one is asking for an entirely new game, that's why they got the expansion for FFXIV to continue playing FFXIV. However, the rehashes has gotten noticably worse due to how long it takes inbetween each patch (the delay between 3.0 and 3.1. the delay of the anima quest). In a sense, it's "rehashing, but they're doing it worse" and the fact that they're continuing it for such a long period of time. Try to look at it from their perspective to why they feel it's a problem.
For me, the new job, specifically MCH feels like a reskinned BRD at times, and some jobs feel largely unchanged, if not regressed in their road to 60. We're getting one less dungeon per patch cycle so it feels even more repetitive when we do roulette, Alexander does not do much different in regards to presentation from normal to savage mode (see normal/hard and EX primals for example).