I'm surprised that Rosetta 2 isn't installed by default. It seems that for the next couple of years the vast majority of people will need at least one x86 app. I guess split-architecture applications were also not foreseen as it is clear that the auto-install prompt doesn't work very well in that case.
"X% of machines have installed Rosetta on this version of MacOS" would be a useful number without measuring the specific executions.