The difference between my proposed policy and the ones you are discussing is that I would suggest that there should be some amount of funding for it coming from the government. I wouldn’t object to parents being able to invest some additional money into the account, but I don’t think it solves the problem if parents are the only ones contributing. Kids already put a strain on finances, and most people aren’t going to invest money they need today in an account that won’t be touched for more than half a century. Lower income families in particular would get the most benefit from such a program and would be the least likely to use it unless it was funded by the government.

I wouldn’t even want to make this an optional program, I’d say the account should be created automatically and parents can gain access in order add money of their own or possibly to adjust the investments among a defined set of options. When a kid comes of age they would be able to claim the account, and they should be able to contribute to it with a withholding from their paycheck.