The sum total of mutations necessary to achieve immune escape and overcome herd immunity is a lot more likely to come at a cost to overall fitness.
Also I can't guarantee that West Ham United won't win the Premier League, but the safe money is all on Man City.
Paper on the possibility of mild disease endemicity:
https://science.sciencemag.org/content/371/6530/741
AP coverage of that paper:
https://apnews.com/article/common-cold-india-coronavirus-pan...