> Alcohol let our ancestors survive.

Only true in dense cities and perhaps onboard seafaring vessels. Most of humanity could find unpolluted sources of water.

You could also say that, without the crutch that was small beer, humanity might have been motivated to learn and implement water treatment/purification techniques and proper sanitation systems centuries earlier.

Edward Slingerland Haha written about a hypothesis that beer was the major reason for inventing agriculture. I don’t know how well received that theory is, but it was an interesting and unique take

I recently read that that’s a myth, unfortunately.

Brewing typically involves boiling. That can kill a germ or two, or so I've read. That's true for brewing tea as well.