This sounds reasonable but mountain lions and many other types of non-domesticated cats still purr (https://parks.sccgov.org/plan-your-visit/park-programs-event

This sounds reasonable but mountain lions and many other types of non-domesticated cats still purr (https://parks.sccgov.org/plan-your-visit/park-programs-events/more-explore/how-puma-purrs https://parks.sccgov.org/plan-your-visit/park-programs-event...). You might be right that domesticated cats have evolved behavioral traits to purr more than their undomesticated counterparts, but I doubt the trait itself is linked to domestication since it still exists in the wild.