So far, the "reservoir of selfish unvaccinated individuals" that the virus has mutated in is people who literally could not get vaccinated because there weren't

So far, the "reservoir of selfish unvaccinated individuals" that the virus has mutated in is people who literally could not get vaccinated because there weren't enough vaccines available. The most important variants so far have showed up in the UK before any vaccines were approved, South Africa during their vaccine clinical trials (rendering the vaccine they were planning on using effectively useless), and India which is just too big to vaccinate quickly at current production levels.