Disagree. There are plenty of great people who could be in office. The problem is that due to the corruption, money, etc. the power of incumbency is way too great.
Since Congress has no interest in reigning in the corruption that increases the power of incumbency, we need term limits.
Incumbency becomes too great an advantage, as you say. Maybe a compromise would be to term limit the number of consecutive terms. So an incumbent would have to sit out a cycle after “X” number of terms, but could return after the respite, running as the non-incumbent?