The problem is closer to whether the spike protein is near an local maxima for infectivity since it's involved in binding to ACE receptors. Since mutations in COVID seem to conserve the spike protein region, it presently looks quite likely that it can't be changed very much without performing worse. Hence the viral replication optimum: spreading to more individuals makes the virus dominate the population quicker.
Evolution does whatever leads to more of the successful thing existing, so viral loading was a pretty obvious move: the question is whether there's any vaccine-evasion which doesn't compromise that advantageous (Delta suggests yes, but its possible that's as far as it can actually go).
Evolution does whatever leads to more of the successful thing existing, so viral loading was a pretty obvious move: the question is whether there's any vaccine-evasion which doesn't compromise that advantageous (Delta suggests yes, but its possible that's as far as it can actually go).