Quote ="wrencat1873"if/ when a variant arrives which circumvents the vaccine, we will be royally screwed.
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Thankfully that's highly unlikely. The vaccines generate an immune response to the critical part of the virus used for cell invasion. It can only change so much before it becomes unable to invade the cell. In all probability mutations that completely avoid the vaccine induced immune response (if that's even possible) would not be able to replicate via cell invasion and immediately disappear.
We've made a lot of variants of the spike protein - around 45 so far - we can see how little there is left to potentially change. Mutations need to not effect the 3D structure of the protein to the point where it becomes unstable.
I agree with the rest of your post though. The death rate amongst young people is low but it's not zero. The difference between Covid and flu is that we have highly effective vaccines against covid, we don't currently against flu. In essence by not waiting until all over 18's are vaccinated (just a few short weeks) and allowing infections to spread rapidly, people will die who have no need to die.