If true, then
does not follow. I owned the Prius Prime in 2017 and plugged in every day so that my 90 mile commute was improved by the small pack. I averaged 90 mpg. Since I also used the car to take 500 mile r/t drives 2 or 3 times a week, it was used exactly as you described. But then I swapped it for a Tesla, and the pure EV was much, much, much better in all respects. It comes down to this: so long as the EV covers the long trips (or you have some alternative arrangement), the PHEV is markedly inferior in real life. On paper, it shines.
^^ That Prius Prime year was while I worked, and drove a lot. Now I am quite satisfied with a mid-range EV only. We rent for the other occasions.
The average commute in the US is 27 miles. The RAV4 prime has a pure electric of 41 miles. I think it’s pretty easy to understand what I was saying.