Economically, the only thing that makes sense is a tax funded defined benefit universal system.
I think I made this point before here, but the problem with the 401k model is that you're asked to answer impossible question - how much money will you need for retirement, and you can't know it without a crystal ball (well, at least since the fat cats at Washington banned Miss Cleo).
You can figure out the average amount required to retire, but what good would that be?
You do that and you still probably running a 30-40% chance of running out of money and dying in the street (or burdening your children).
So the only smart move is to oversave, not everyone can do it, but even if you could, that still a whole lot money going to wall street that could've been used by more productive members of society.
The problem is that you bare 100% of the risk, wherein if you share the risk with the entire population, you only need to "save" (in this case, taxed) by the average amount required (which is very easy to figure out too). That's billions (if not trillions) of dollars that can stay in the real economy. okay, probably not trillions, but many billions most likely, like hundreds of them or something (I really couldn't a figure about how much do we contribute to 401k as a nation in a year).
p.s.
You do this and as a bonus we get to collectively stop stressing over that issue and we can once and for all stop pay attention to Wall Street.
That's the biggest con those fuckers pulled, we're all pretty much forced to play in their shitty little game and it needs to stop.
The great recession couldn't have happen (or at least couldn't have happened to that extent) if those fuckers didn't have all of our pension money to play with.
Edit: I've been in this country for over a decade now, I traveled it far and wide, I've seen many different people with many different opinions, I have never met a person who like the 401k model who didn't work in the financial industry.
Not a single one.