In my opinion, Solterra sales
In my opinion, Solterra sales will dictate follow-on electrification (hybrid or BEV) of current models, but unless people stop buying the current models they are not likely to change drastically. Subaru already tested the hybrid waters (I had the 2014 Crosstrek Hybrid and traded it in because the mileage was getting noticeably worse than their other model ICE cars), but they won't bring the current Forester hybrid to the US because we are such whiners and won't buy unless there's a Prius-like gain in MPG (I would be guilty of that thinking as well).
I'm hopefully optimistic about the Solterra and have been following solar shingle development for decades to reduce charging cost. Seems like the time is finally right for mass adoption of distributed solar with the additional benefit of home battery systems becoming more affordable. Now we just need a massive federal boost (assistance plus tax breaks) to get ourselves more self-sufficient and ease the stress on the electrical distribution infrastructure as everything moves away from burning things to create energy.