It's fun (until some takes it too seriously).
Oh I absolutely agree. Fun to play "what if?"
In that vein, I really think the days of the mid-sized BOF SUV and pickup are numbered.
The reason for this IMO is that the makers of these vehicles are between a rock and a hard place in terms of how big they make the vehicle. Make it too small and people won't buy it, make it too big and it might as well be full sized.
This is a problem for Toyota and Nissan and the other because every company out there that makes a mid-sized vehicle
also makes a
full sized vehicle. So if they make the "mid sized" too big or powerful or nice, they cut into sales of the "full sized" models and since those are bigger money makers, they don't want to do that.
IMO this is also one reason why Toyota dropped the V8 from the 4runner (and why we'll never see a V8 4runner again): It cut into sales of the much more expensive 100 series LC and Lexus V8s.
CAFE is the other culprit. There seem to be a lot of strides being made in improving the MPG of full sized vehicles like the new F150 and Ram. But with the mid-sized or compact-size trucks and SUVs, there's not a lot they can do if they still want to retain the BOF structure.
The most sensible way to go for Toyota would be to do what Chevy, Ford, and Nissan have done: Dump the BOF architecture in favor of a lighter, more fuel efficient unibody design and as for those few customers you might lose because they want a rugged, BOF design, sell them a full sized truck or SUV instead.
I think it's worth noting that there was a time when the only "compact SUV" out there was the likes of the Jeep CJ, Land Rover 88 or Land Cruiser FJ40. Back when I started 'wheeling in 1979, "compact SUVs" weren't even really a thing. If you went 'wheeling you either had a Jeep (which may have been "compact" in size but was otherwise similar to a truck) or you had a "full sized" SUV or pickup (FWIW my first vehicle was a 1957 International Travelall, 4x4.)
IMO full sized SUVs like the Suburban, Tahoe, Expedition, and Sequoia will always be available, as will the full-sized pickups they are derived from. Those vehicles have dedicated "market segments" that will always buy them (companies or individuals that need work trucks, people who pull heavy trailers or 5th Wheels, government agencies, etc.)
But the "compact" BOF truck and SUV occupies a shakier space in the market. They're not as capable as a full-sized and they're not as economical as a unibody car or crossover. They're "neither fish nor fowl" and as such, I think they'll disappear from the car market except in very small niches like the Jeep Wrangler.