I see. there was another similar study that touched on what I mention. I assumed it was the same https://www.transportenvironment.org/uploads/files/2025_09_TE_briefing_PHEV_gap_growing.pdf

I think the issue is driver be shoot more than the car.

eg.

-many companies bought plugin hybrids for corporate cars and handed them to employees since they would get some incentive, but employees did not have chargers at home so they just used them as a regular car.

-people buying them to get easier parking in the EV reserved spots

twice I rented out a plugin hybrid and both times it had the battery empty (around 2021)