Provided the limit is tied to inflation and does not require Congressional approval to increase, I don’t see what the limit with this is. It’s not a limit on how much you can save for retirement, just a limit on how much you can save in tax sheltered accounts - a limit which is pretty high, considering the contribution limits.

I think this kind of thing is more aimed at the really fancy shenanigans pulled by some folks (like, oh, Romney) where certain types of stock were put into an IRA that allowed it to explode in value, compared to what most of us ordinary Americans are stuck with.