Term limits are in the hands of voters.
We proved that when we Cantorized our weasel, the sitting Majority leader.
And if you put a mandatory retirement age of 72, he’d be out.
If voters were always wise, and never voted against their own interests or the country’s interests, then you would be correct. The framers understood that you couldn’t and shouldn’t rely on people to always be virtuous or wise, otherwise, why even bother to have divided government in the first place? The three branches of government were just an attempt to limit the consolidation of power and to provide checks and balances to overreach. Term limits was a check on power that they overlooked.