Instead of two car lines ie Camry and Corolla, now they have four, Camry, Highlander, Corolla, Rav; each requiring engineering, sales, tooling.
Arthur is exactly right of course, margins are much higher on RAV and Highlander than on Corolla or Camry wagons. The CUVs are also much worse on fuel (aerodynamics are aerodynamics, large frontal areas and underbody turbulence are part and parcel of the CUV/SUV format). With fuel prices rising, I'd imagine a return to more pragmatic designs won't be far away.