PHEVs when you already own them cost vastly less in electric mode. That people don't bother plugging them in is because they don't care about cost enough to bother to see if there is a difference.

It’s also because most PHEVs sold are terrible EVs. Weak, short range, cut to gas all the time. Impractical to use as a pure ev. This style of phev is greenwashing and should be sold as a gas car for emissions rules.

EREVs are a different story, and have a place in the transition for awhile.