The problem I've seen is that formal agile processes substantially reduce individual engineers' autonomy—slowing everything down seems more a symptom than the core problem. (Of course, it's ultimately the symptoms that kill the patient, right?)
Coordination is both important and difficult, but a process oriented around tracking and directing individuals at a bite-sized-ticket level is not a necessary, sufficient or even particularly effective solution. It's an abstraction to make work legible in the worst way: it's restrictive to the people doing the work, encourages unhealthy patterns of top-down management, poorly reflects the ground truth while still giving managers the illusion of detailed understanding and control.
As for top-down, organizations try that approach because it seems like the problems could all be solved if people weren't coordinating with each other, but just did what they were told. It seems like it doesn't work like that; this presentation explains it pretty well (and was on HN last weekend): https://komoroske.com/slime-mold/
I don't have any evidence, but I think it's an undeniable fact that coordination effort is very expensive. We are all familiar with how fast our 1 person weekend projects go; you spend 12 hours on Saturday evenings on something, and it feels like it progresses faster than what your team of 30 people is doing at work 5 days a week. My opinion is that projects scale exponentially with complexity. A 1 person project takes 1 person. A 2 person project takes 2 people. But then, a 3 person project takes 4 people. A 4 person project takes 8 people. A 5 person project takes 16 people. By the time you are at big company sizes, you might have 30,000 people vaguely working on the same thing; by my rule above, that's a project that's 15x more complex than a 1 person project. That's why it feels like "my friends and I could make Twitter over the weekend, why do they need 30,000 employees!?" You're thinking that results scale linearly over the number of people, but it really scales logarithmically over the number of people. So now you're 1/30,000th of a 15 person project, and you don't feel as productive. You are 0.003% of the equation. If you work 10x as hard, you're 0.03% of the equation. It just doesn't fit with your mental model of productivity that you extrapolate from personal projects (where it's 100%, or 110% if you had a really good cup of coffee). That's why it feels bad, but it's also why management is not super concerned that you are spending 20 hours a week in meetings. Oh no, now you're only 0.0015% of the equation.
The final question is, why does society put up with this? The answer is, there is money in these projects that are just a bit more complicated than a software engineer's personal project. You will be remembered more for the 0.003% contribution you had to the moon landing than you will for making the absolute best ever music file organizer. It sucks, but that's how the Universe works. You can embrace it, or you can fight it. But if you want to stave off the heat death of the Universe, you might need a team and a plan and maybe a few meetings to share the plan with your team ;)