The issue of where Omicron came from seems to me to be the one hole in an otherwise compelling thesis: "you saw how quickly omicron chased the vaccination campaigns. my strong suspicion is that this was not a coincidence. it was driven BY the selective pressure of the vaccines that took what looks to be a throwback variant that did not evolve from delta but rather diverged from it all the way back at the original pre-alpha ancestor and surged it to sudden global prominence." I'm not aware of any evidence demonstrating that Omicron evolved. It seems far more likely to be a lab product than the result of selection.