Add to that, the more it multiplies and spreads, the more chance of mutations leading to more variants. Needing updated vaccines, booster shots of existing, and/or higher rates needed to reach herd immunity.

Didn't the UK have another lockdown for this wave too?

Herd-masking seemed like a no-brainer from the beginning. It will be really hard to go back to that in the US after the CDC giving the all clear to go maskless.