I've always looked at it as "1. 401(k) investments are generally worse, higher cost and fewer choices than I could get on my own at a low cost broker (Vanguard, Fidelity, Schwab, etc.). 2. I would rather have control of my money rather than let someone else control it, especially if things start going bad at my current job." As soon as I leave, the money gets rolled over into my personal account. The only thing I lose is the ability to borrow against my 401(k), but I have never been tempted to do that and my last job didn't allow it anyway.
My employers all set up our 401K’s in our own names (but less control until fully vested). Vanguard for the first ones, then Fidelity... I was able to move the Vanguard ones into my Fidelity account. Still 401K with the Federal rules... but I was always allowed to make the investment choices.... I thought that’s how it worked for all of them.... perhaps that was just my case.