In the same scenario that Roth IRAs are at risk of extra taxation (or fees), 401(k)s are as well. That doomsday scenario isn't worth planning for with money, but with physical assets (property, food, tools) and skills because that's the scenario where the US economy collapses (not a recoverable crash like 1929 or 2008, but a true, complete collapse where the USD value goes to zero).

Roth IRAs make sense if you make too much to contribute to a Traditional IRA with tax advantaged contributions and little enough to still qualify for the Roth.

They also (both traditional and roth) have an advantage over a 401(k): You get to manage the funds any way you want. You also get to contribute even when your employer doesn't have one, you just need income (capital gains don't count, as I understand it, so being semi-retired and living off your earnings does preclude you from contributing).

You're also limited on 401(k) investments to whatever your employer contracted for. Could be shitty, could be stellar, you don't control it.