I used to think this but I don't any longer. Two reasons : 1) asymptomatic spread makes infection control much harder and 2) your own admission that it would have required "very heavy-handed and coordinated action across the world". This second reason made it impracticable to stop the spread in March 2020. There are countries in the world where you simply cannot apply such heavy-handed action; there is not the level of control of or essential support for the population available.

Btw, I've looked through your earlier replies to others under this comment, and I have to remark that you took a very patronising tone, which I found unfortunate.