Does anyone have good stats to share on how vaccination impacts transmission? I’m curious.

I was lying in bed for two days until I self-diagnosed with appendicitis and decided to go to the hospital. Turned out I was just in time. What I mean is I won't seek medical help unless absolutely possible (I live in EU countries where medical care is free). Due to this mindset (whether or not you think it's stupid, I don't really care) I'm simply not going to subscribe to having two boosters per year for the rest of my life. I've had two jabs now but as it looks like now I'm probably soon gonna start putting my immune system to work (and travel less as a result I suppose).

There are studies indicating a previous infection provides a stronger and longer lasting response than the vaccine, although this is not definite yet - Israelis and the CDC have made opposing conclusions on this topic.

Presumably the under 30s will get covid within a few years, and then they will be in the pool of people with significant immunity.

Or they could vaccinate and have significant immunity nearly immediately without COVID.

Yes, one of those two things will happen. The point is that the under 30s aren't likely to make it to a different age bracket where they are more significantly at risk without first achieving immunity in one of those ways.