And no it doesnt follow that everyone will get covid and end up in hospital, it will just take longer to happen
This is what the Warwick and other models show, can you please cite your alternative evidence?
Lockdown doesnt necessarily reduce fitness, unless you ban people from exercising in their homes - that is a choice people make
Plenty of evidence that this is exactly what it did - you are perhaps under the illusion that it is "exercise" that most people develop their fitness from, it's not, most people don't exercise, they get their fitness from incidental activities or from team competitions.
We can say "people should just exercise in their home", just like we can say "people should lose weight so they're not vulnerable to covid", but it's insulting simplification that doesn't actually achieve anything.
accept infections in low risk groups to rapidly confer population immunity It's been shown that this doesnt work. The young transmit it to older age groups who end up in hospital
Again, some evidence? As we do have evidence of the reverse.