> In terms of drive train these are more complex to manufacture and more costly to maintain than an EREV
They really aren't, an EREV needs two electric motors and fixed gears connecting to the engine and wheels. Toyota-style hybrids (also Ford, Chrysler, Subaru, Mazda) need... two electric motors and fixed gears connecting to the engine and wheels. Everything else is quite similar, though the hybrid will obviously have much smaller and cheaper batteries, onboard chargers, battery temperature management systems, etc.
They really aren't, an EREV needs two electric motors and fixed gears connecting to the engine and wheels. Toyota-style hybrids (also Ford, Chrysler, Subaru, Mazda) need... two electric motors and fixed gears connecting to the engine and wheels. Everything else is quite similar, though the hybrid will obviously have much smaller and cheaper batteries, onboard chargers, battery temperature management systems, etc.