Why hasn't Toyota gone rear wheel drive only if is was a wise choice for GM's crown--Cadillac. Not enough torque steer for Toyota vehicles?

2005 AWD Escape Hybrid
Best Interstate tank trip MPG 39.02 (scangauge II) for 402 miles on I-70, 10.3 gallons used over mostly flat terrain.

Best Interstate tank trip E30 MPG 34.6 for 271 miles along I-80 in Indiana and Ohio.

Best multiple road tank trip E30 MPG 36.2 for 202 miles in Southwestern Pa.