95% is a bit of an exaggeration, it's more like 30-40% inclusive of ALL Hybrids including the Prius. The one factor you're missing here is that many drivers consider a somewhat expensive non-hybrid luxury vehicle as an investment because they're able to solicit higher tips.

This hasn’t been my experience at all, unless you mean airport pickups, which indeed is mainly priuses due to regulations by the airport. However, for regular trips in town, you rarely get to ride a prius (because they are too busy serving these profitable airport routes)