Very true. It's obvious to most political analysts that African countries are in trouble because each set of leaders that comes into power goes for the short-term gains. To a leader with sufficient longevity, one has to think this would eventually become evident. Sort of the "immortal bandit" version of the "stationary bandit" theory.
It's the only absolutely reliable way of getting rid of bad leaders.
This might not be a good enough reason to oppose longevity tech, but I don't think it's easily disposed of.