Not really, because the process is very gradual. You don’t sell all your stocks the day you retire, you gradually wind down until you hit some reasonably conser

Not really, because the process is very gradual. You don’t sell all your stocks the day you retire, you gradually wind down until you hit some reasonably conservative allocation in your 80s or so like 30% stock/70% bonds. This certainly can put some downward pressure on the stock market if the rate of this winding down is higher than the rate that young people are adding to their 401ks but it’s counterbalanced by many other forces.