The stated goal of lockdowns was to "flatten the curve." The working assumption was that the virus would become endemic no matter what we tried, but by limiting interpersonal contact, we could decrease the rate of hospitalization to a manageable level. It is not reasonable to declare the lockdowns a total failure because they didn't achieve a goal they weren't intended to solve.

Sure, and it would have worked with COVID as well IF there was close to 100% compliance AND you could sustain that for 2 to 4 weeks. The only place that had real lockdowns where they actually welded the doors of people's apartments was China and they did effectively stop the spread of COVID until the much more contagious omicron came along. By then people were weary of lockdowns and the protests started threatening the government.