You got approximately 160 hours of 6.0 MSQ and roughly another 20 hours of 6.1-6.5 MSQ (part yet to come).
You got 13 new dungeons and 7 new trials (final of each upcoming in 6.5).
You got Pandaemonium.
You got Myths of the Realm.
You got Sil'dih Subterrane and Mount Rokkon with 3 different difficulty modes each.
You got Dragonsong's Reprise Ultimate.
You got The Omega Protocol Ultimate.
You got Eureka Orthos.
You got Island Sanctuary.
You got 2 new world boss level FATEs (Chi and Daivadipa) in addition to all the other new FATEs.
You got new crafting and gathering recipes and leves.
You got Tataru's Grand Endeavor.
You got the Somehow Even Further Adventures of Hildribrand.
You got the Manderville weapons.
You got the Omega sidequest.
You got the Splendorous relic tools.
You got level cap on all jobs increased by 10 to 90 (Except BLU which increased to 80),
You got Crystalline Conflict.
You got a new Leap of Faith puzzle at the Gold Saucer.
I'm sure there are some other things I'm forgetting but the general point is you paid for new content and you got new content. This expansion is not lacking in new content compared to Shadowbringers. Most of those things can be done repeatedly.
What is missing is your interest in and engagement with that content. That is what needs to be addressed.
Where did it miss the mark?
We've been trying to point that out for a while but few of those who are unhappy seem to want to acknowledge that it's interest and engagement lacking, not the amount of content to do.
One thing you didn't mention that I think has had a big effect is the 2 minute meta. Beyond the general issue of job design (also a problem), the 2 minute meta has effectively removed some player agency and that makes things less satisfying even if that agency is sometimes more illusion than real.
If the 2 minute meta is back for Dawntrail, then we'll truly know the developers don't pay attention to player feedback.
No one is shielding SE from feedback unless it's the trolls stirring things up into personal arguments instead of constructive discussion.
The opinions of casual players are just as valid as hardcore players. Both are paying a subscription for the game. SE needs to take both into consideration.
I've said this in the past. I think part of the problem is this is a transition period for the game. Yes, they are focused on the new player experience heavily because they're trying to make the game friendlier to new players and give them a new starting point other than Gridania/Limsa/Ul'dah. We were told during the 10 year roadmap LL that the 6.x series was going to be that transition and so things wouldn't be quite what we were used to.
The important thing now is to make certain SE knows what changes during the 6.x patch series have negatively affected player engagement so they can be corrected in Dawntrail. That means people need to list their feelings clearly and constructively. The personal bickering needs to end if the feedback is going to have a chance of being seen.
Being negative is fine when it is being constructive. Engage with that - questions can help reveal useful information.
But do avoid engaging with the negativity that has no purpose other than being negative.