Whether or not you want to is an entirely different question, of course.
Our youth is when the majority of what we do is try things out to see what fits and what doesn't. In our older years, most of that experimentation is behind us and we have a pretty solid idea of what fits us and what doesn't.
The trick is that the amount of experimentation should never be reduced to zero.
By X, in a single career, you've generally got a pretty good handle on things (and life).
In contrast to 20/30, when everything is constantly new and you are constantly uncomfortable.
Thus, big difference in how well the uncomfortable muscle is exercised. 20/30 -> novel situation you suck at -> business as usual. Over X -> " -> WTF.
And, as you say, the key to retaining that capability is... make sure you continue exercising that muscle!
Something something about age and responsibilities and tiredness and not having trained for that, but... it's worth it to think about it, anyway — at least as risk-mitigation for yourself, going forward.
Maybe we'll all end up as plumbers?
Not everyone can become an architect or water systems engineer at 50, after having worked a "general assistant" type office job for many years.
I think that (and its consequences) might be the biggest short term societal risk of automation in an aging society.
How would you solve this problem?