The Reason Why Are Trucks Getting Bigger

What's weird to me is that this, again, is such a uniquely American problem.

While in Europe cars have also increased in size, I believe the largest of them is at least a magnitude smaller than the abomination that is Ford F250, for example.

Probably but where I live in EU i see a lot of big trucks imported secondhand from the US. People like big cars.

I don't have a big truck but I also don't remotely think it's a "problem" that some people do.

Driving a truck like the F-150 would severely limit your mobility in most of Europe, even in rural areas. You would be unable to drive or park in most of the city centers, and rural roads are often fairly narrow as well. So you would generally be restricted to driving on major roads.

Further, American-style trucks are not considered "classy", those with $50-60K to spend on a vehicle would likely prefer something like a Mercedes.