It feels like (at least in my country) all the lockdowns were part of an experiment; try something else, see if it works. At some point they tried a curfew for a few weeks, it had an effect but people didn't like it and enforcement was a huge issue (naturally).

The other thing is that every time a measure was effective, they would stop doing it so that the cases would go back up again.

That said, as China proved, a totalitarian lockdown (where people were locked in their house) didn't work in the long run either. China got back to productivity faster though, and gave their population time for a vaccine to be developed and distributed.