If you believe this is going to happen you can change the allocations of your retirement plans.
Saying you as in any random person can protect themself from a group of dedicated experts who also have access to levers the common person can’t pull, is kind of not believable on its face.
There's maybe, at best, 1% of the country even aware that this might be a problem.
If you're really worried and want to be conservative tell the portal you want to retire in 2030. That will allocate your investments to something conservative and you'll be more protected from a downturn. On the other hand, you'll also be equally protected from an upswing.
/not a financial advisor