Most of these points apply to pensions too. Getting laid off two weeks before your pension vests is an all too common story. Companies go bankrupt and the judge rules the opposite of what he did here. Pension plans themselves can go bankrupt, and although they're insured, it's only up to a certain limit.
And most of your 401k is going to be the money you put in, not the match anyway. So it sucks when you aren't able to vest or your employer doesn't match well, but that doesn't kill the concept.
The formula is proven to work in other countries. My point is you can't refuse to use a defined contribution scheme and then complain it didn't work.