Part of that is that we are reaching the point where a plug-in hybrid is actually more expensive to produce than an EV.
Go to Toyota's website today and you'll see that a Rav4 Plug-in Hybrid is more expensive than the bZ which is the equivalent full EV.
Going to an EREV layout (a series plug-in hybrid where the gas engine cannot drive the wheels mechanically) doesn't really save any costs directly, but allows sharing the platform between EV and EREV models.
Go to Toyota's website today and you'll see that a Rav4 Plug-in Hybrid is more expensive than the bZ which is the equivalent full EV.
Going to an EREV layout (a series plug-in hybrid where the gas engine cannot drive the wheels mechanically) doesn't really save any costs directly, but allows sharing the platform between EV and EREV models.