Oh, so easy answer for you!
Out of all of the various lanes of play, you scope yourself down to but a handful of them. This is perfectly fine and what most people do, but your handful is not the majority handful nor the only handful.
The majority of WoW players spend more time in world content than any other. In this lane, mount/pet collection and achievement hunting tend to be hand in hand. Dragon riding is more engaging than just flying up, pushing num lock, and checking your phone for a bit.
But it also breaks up the tedium of farming! While the old flight would allow me to autopilot and farm while watching a show, I’m actually paying attention and appreciating the details of the world around me for the first time in over a decade.
So why might dragon riding save the game? Well THAT is the short-sighted take, but the nuance is that Blizz managed to not only execute 5he riding really well, but more importantly, they managed to craft the world and world flow with it in mind really well.
They’ve also been on an effort to revamp much older content that players lament sitting around and rotting, and it’s where these two things intersect that you find your answer…
…they’re televising a slow and steady revamp of the core play experience, of which dragon riding bestows great confidence in regarding an area that’s traditionally been a weakness.
Now, not every player is going to articulate it as such, but this is the core of what’s going on.
And it IS a good thing if they keep the momentum, pun intended, as “end game” could one day include older content on a rotation with new affixes in a season, much like the boon of M+ we’ve been seeing
So it’s a “total package is doing the saving” with “but dragon riding demonstrates a commitment to a desired vision”
And for players such as you, who prefers narrower lanes of play? Well, casuals pay the bills! Revamping 5he leveling and casual experience is how you grow a new generation of players, and those players are cash money, and cash money is the largest bottleneck to the content you prefer!