Spanish flu’s mega waves stopped though. My point is if covid keeps swamping us then we won’t be able to ignore it.

Easy to say “I’m done with covid” at the bottom of a wave, which is where most of the world is now. (Referring to the popular attitude, not you)

Hasn't influenza been around for like 1000+ years?

Influenza has existed in human populations for a long time, yes. However the 1918 pandemic was a novel H1N1 influenza A probably from birds. It was never eliminated in humans and continues to kill people to this day. We "learned to live with it" because up front capital costs are distasteful to idiots who can't see past the next quarter.