That is the other half of this issue.
When the wave of boomer retirements hit, they will stop putting money into the 401 (k) and start taking money out. Which will depress the market.
Be aware that the 401(k) plans have large risks also
They certainly do, but they're getting to be all we've got. I think the only thing we can hope for is that the social chaos which would ensue if they all tank would be unthinkable. I have more than half a million dollars in mine and it's not nearly enough - fortunately, retirement is still more than ten years off. But I think a phased drawing-down of funds is the way to go; I don't think anyone is going to want the tax consequences of taking too much out at once.