Was talking to staff at the rental counter in Phoenix. They said that they stopped buying hybrids when gas dropped back down and the fact that they were costly to maintain... (More moving parts).

Fleet sales were a big driver when gas prices were higher

Plus, hybrids are a gutless jack of all trades and master of none

Depends a lot on the hybrid. Prius is the most reliable car you can buy. When I sold mine at 130k miles, it still had the original brake pads. You are right about the jack of all trades, and IMHO that's a good thing.

The hybrid transaxle on the Prius is a technological marvel.

While the transaxle and battery pack add their own significant costs, complexity, and failure modes, they also eliminate a lot of the components on a conventional gas engine vehicle.

In my area, it is common to see a lot of hybrids used as taxis. Some of the older ones I see likely have 500k miles.

Same here, I thought hybrids were a lot bigger market. I'm surprised that ~90% of cars sold are still non-hybrid ICE cars. (I don't live in California, but I assume their numbers are fairly representative of the rest of the US.)