That is what you said. Difficulty scalable dungeon tech does not benefit any recent WoW players. Truthfully, it would benefit XIV players substantively.
Bolded is absolutely false. In the context of savage raiding, gear is a means to a goal. Raiders care about gear—including world first raiders—because at some point that gear will be needed to successfully overcome the challenge, but it is not the reason to do the content. Raiders do savage for the challenge, period. If the entire expansion's raid content could be cleared without gear, participation would remain the same. It's not the reason for participation.
You also know for a fact that "people" as you put it hated Alexander because of reasons? Funny how a lot of people enjoyed Alexander...
Sorry but you're absolutely wrong. You are thinking of stereotypes long discarded. Raiding for prestige? Do you honestly think anyone who successfully completes content cares what people outside of their statics / FCs thinks of them? They don't. The only people who seemingly care are the try hards who think what someone does or does not do—that does not affect them in any way—actually matters (and it doesn't matter).
Raiders do it for the challenge and, as you said, complete the content. Old content isn't done because it's old, been done so many times, and they want something new.
Once again, in your example, it is longer, not harder. When you take your gear off, the boss does the exact same damage and has the exact same health. The only thing different is that you are statistically weaker, and thus, the fight takes longer.
What am I after? Actual harder dungeons, and not simply longer dungeons, as you are suggesting.
Mythic+ isn't perfect and there are issues. The weekly cache is an issue (thus why people stop at +10 / +15). Exploiting the system in its infancy for titanforging is an issue (and as an aside, titanforging is also is an issue).
But does this mean the good of the system should be discarded?
No, such absolutist thinking has no place.