[Delmania]

"An arbitrary deadline, often forcing you to interrupt your flow and then spend extra time next sprint reorienting yourself to pick up the same task again. And artificial accountability. (Did Alice overrun her time-box because she was lazy? Or because the bug was really tricky? Nobody knows! Is Bob a rockstar, or is he just really good at plausibly over-sizing small tasks? Perhaps!)"

You know at least 2 weeks in advance you have to be able to give your customers a report of your findings. If that interrupts your flow or forces you to "reorient" yourself, that sounds like you have poor planning and time management skills. If Alice is consistently missing her deadlines, or if Bob is consistently over-performing, the team needs to analyze the tasks being given to those individuals.

"That's kind of strawmanny. In no methodology should someone be allowed to wander around for months with zero feedback."

There is a difference between "go research this and report back" and "go research this for 25 hours and get back".

"I have literally never met a customer who didn't want everything right now. A good traditional PM is able to manage those customer expectations. Few developers I've met have those skills or want to be spending their time doing that."

Agile and the constant feedback cycle help to manage those expectations. It's another tool in the PM's toolbox.

Of course they all do. Another fundamental part of agile is the constant communication between customers and the team.