"When the unvaccinated population rises too high, outbreaks become possible again"
Not really, outbreaks only are potential for those who are unvaccinated. If 5% are unvaccinated, and 95% are vaccinated. Even if an outbreak happens in the 5%, most all of the 95% who were vaccinated should be safe. Yes, there may be a few exceptions. But very few.
Want to know the real cause of the outbreaks. The ones the media blamed on unvaccinated, most eventually determined those who were infected were ALL vaccinated. The real issue is that the vaccines are several decades old, and while science teaches us that said viruses rapidly mutate and evolve to knew strains. We're using vaccines based on strains sometimes almost a century old. Which greatly reduces their efficacy.
But here's the catch. It's expensive to get FDA approval on a vaccine update. Furthermore, the pharmaceutical corps have millions of dollars invested in stocked vaccines and rooting compounds. So much easier for the FDA and big pharm to claim it's because of loss of herd immunity, when in fact it is because they are using extremely dated and ineffective vaccines.