A good project manager is worth their weight in gold. Large scale projects are complex and have lots of moving parts. Someone who understands this and is good at keeping all the "parts" moving while heading off any potential issues is extremely valuable.
The problem is that often the people doing the hiring don't know what it takes to run a large project, much less what good project management looks like.
They just hire some idiot with an agile certification whose only skill is moving items around a kanban board in a way that gives the illusion that progress is being made.
Another problem is when management somehow manages to make a simple project into a crazy complex project.
I see two drivers of this:
General empire building, more headcount under me == I am more important
Trying to use unvetted, low quality labor to do something being their abilities and trying to make it up with volume because corporate leadership declared it should be possible and anyone who says otherwise it's a bad fit for the company.
Our project managers are salespeople, they over promise our capabilities, mostly because they don't even know what we can do, and disappear the moment a contract is signed. Leaving it up to the employees who actually do the work to meet impossible expectations.
There's been a few good project managers who get involved and check in on things, but there's only been one (out of a dozen+ or so) in my 7 years working here who's actually asked us what we can do and how long things take before taking in contacts. I'm sure they, or at least that kind of approach, will not last very long.