In practice I think he is right unfortunately. Most people would just run Chrome and more websites would require Chrome since they could just tell Apple users to deal with it, making the mono-culture even worse.
Maybe the answer from Apple should be to improve Safari instead of restricting competition.
FYI:
...fewer sites...
...if Safari were...
Then Safari also is the last non-evergreen browser so it's the slowest to update compared to all the other browsers. If you have a bug, there's a good chance you'll have it for years
But "non-evergreen" doesn't mean anything.
Call it with another word if you want but Safari is on a league of its own.
Sad to see supposedly technically-knowledgeable people cheerleading for regression.