Yes, I agree that there is a temptation for those in power. Legal frameworks can be created to try and limit the lengths and conditions under which a "crisis mode" can be enacted, but there will always be people looking for more power.

If anything COVID demonstrated the opposite - governments were all too eager to get back to BAU despite the situation still being severe, resulting in notably high excess death rates.

I think they were tired of defending indefensible policies.

Politicians are experts at that surely. But in this case I'm not aware of a case where any epidemiology or other public health policy experts were telling governments lockdowns needed to be ended. The cynical side of me suggests that there were too many at high levels of government who felt that lockdowns impinged on their ability to enjoy the levels of power they were accustomed to that, and so the opinions of those whose job it was to advise on such matters simply got overridden.