A couple of comments on that.
1-Trucks have lower emission standard requirements from the EPA than cars do. The 7.4 Triton and 8.0 V-10, et al are for work trucks that need the hoses and torque to haul heavy stuff.
2-the big engines in cars now a days are for specialty cars and the get huge gas guzzler taxes (or squeak by mpg regs by using variable displacement systems). Gone are the days when you could buy a chevy station wagon with a 409 and three 2bbls, of a four door Newport with a 426 max wedge and cross ram two 4bbls.
When my gf was buying her malibu, I looked at the window sticker on a vette. Granted, it was the loaded to the gills ZR1 supercharged, but the gas guzzler tax was almost as much as the sticker price on my Yaris.
Also, technology has come forward by leaps and bounds. My definately non-sporty Yaris has a 1.5l engine rated at 106hp. The original 283 v8 SBC was rated at 162 hp. You can now get a whole lot more hp and torques for a lot less displacement. Add in direct ignition, direct injection, and small, high efficiency turbos, a 4 cylinder can out muscle the muscliest of the classic big blocks. Granted, they wouldn't hold a candle if you modernized the big block, but that would fall into the EPAs gunsights (426 hemi with DFI and DHEI [drool]).