Most people dont need a 3/4 ton truck of ANY kind. But lots of people have a need for a mid to smallish sized suv or “truckish” vehichle that can tow a boat or small camper. Consequently I think the small trucks (colorado, ranger, tacoma sized) with diesels make a lot of sense, as do some of the half-ton trucks. These are all over europe and the rest of the world, I have been told the emissions laws in the US are different which makes the diesels more difficult to sell…not that they are more or less strict, but measuring different things.
I had a 2017 diesel colorado for a couple years. It was quiet, efficient, drove great as a daily driver, and towed (and stopped) a full sized bass boat up hills every bit as well as my v8 1/2 ton. I got an average of about 24 or 25 mpg including commuting and towing the boat on weekends, etc, and on a hiway trip would often get 32 or 33mpg. At the time, based on the relative cost of gas vs diesel plus DEf, oil changes, etc, I calculated the total cost of buying, running and owning it for 100k miles would be about the same cost-wise as a same-size/same trim level gas rig like a tacoma—that has changed as the relative price of diesel has gone up significantly. I traded it in for other reasons, but simply based on how it performed Id own a half-ton diesel truck in a heartbeat if cost was competitive.