> If a website uses fancy new browser features and works for 98% of the population, that means that it won’t work for ~150 million people.

Yes, because all of us have website serving, checks notes, the entire world...

98% is probably in the neighborhood of 8% more than I'd require for browsers compatibility before deciding to use a new feature. At a certain people need to update and we do ourselves and our other 98% of customers no favors by catering to the lowest common denominator.

See also, the story of YouTube adding a banner pushing people to upgrade off old IE version being a large factor in people upgrading. Now, obviously, we aren't all running YouTube-sized sites but building for ancient browsers is, very often, a large waste of time.

In the age of evergreen browsers you have to go out of your way to be using something that's not at most a couple years out of date.