Not term limits but a maximium age. How about we set 80 as the oldest you can be to run.
I think you’re going to run into discrimination laws then.
An incompetent 80 yr old is not likely to be elected for the first time (or if he or she is, that means this person is actually capable of the job and was capable of campaigning). Most of the 80+ or even 70+ elected reps are people who have had multiple terms.
Limit them all to two terms in whatever position it is, and the problem would be solved.