I am not sure if I would go that far. The John Hopkins Study definitely provides some interesting data, but should be used a jumping off point for more studies. The study, which is actually a compilation of results from many studies, points out that it excluded a couple early studies that did show a benefit, so it would be good to understand the difference. Maybe there was a benefit in the very early days because it gave us time to get a handle on what was going on and put other mitigation measures in place.
It also didn't conclude why the lockdowns didn't work. With a respiratory virus it makes sense that reducing contact between people should reduce spread, so we need to understand why that didn't work.
"Our main conclusion invites a discussion of some issues. Our review does not point out why lockdowns did not have the effect promised by the epidemiological models of Imperial College London"
It also says that closing non-essential businesses lead to a 10.6% reduction in fatalities, so maybe we needed to be more targeted with restriction.
I do hope we learn something from this whole thing, but I am not optimistic.