No one really wants a truck with that little power and torque. I don't even think it has to do with fuel economy. I think it comes down to price. In 2010 when Toyota introduced the 5th gen, they included an I4 for what would seem like cost purposes alone (MSRP $27,500 for a base SR5, RWD, I4). They effectively created a vehicle that ranges almost $20k in price to cover every type of driver that could want it (encouraging more sales).
On a side note, I'm not sure who at Toyota decided this, but in the late 90s/early 2000s, they decided to saturate the SUV/CUV market. They now offer (by their interpretation) 7 vehicles that fall into that segment. What's totally genius about it is that the average consumer who's looking to buy one of the SUV's would typically never consider any of the others. And nearly everyone who's looking to buy an SUV need only stop by their Toyota dealer and they can get exactly what they want at the price point their looking for (though I honestly can't speak to who exactly is buying the Venza).
Merry Christmas!
OA