Right. I read somewhere a comment that you can go to Europe and (possibly exaggerated for emphasis) see Audi station wagons towing horse trailers at 100mph on the freeway.
Here, you have someone who might move their single horse from summer pasture to winter pasture, and as a result, thinks that they "have" to have a HD3500 "dually".
There are a few things that contribute to this oddity (never using light vehicles to tow in the US)...
Speed limits. Americans generally refuse to slow down when towing. In most of western Europe, the speed limit is 20mph lower (give or take) when towing. In order to tow at a high speeds while maintaining stability, you need a long wheelbase and mass.
Liability and fear of lawsuits. My 2017 VW Sportwagen is rated to tow 2000lbs in the EU. It isn't rated to tow AT ALL in the US. There are no mechanical differences that would impact the tow rating. If a consumer wants a vehicle rated to tow, they literally can't use a mid-size sedan or wagon in the US (despite the exact same vehicle being able to tow a small travel trailer, horse, or small powerboat without problem).
Volvo never played this game. The tow rating for small sedans in the US is as high as in Europe. While I don't max it out or come even close to the limit, I hauled plenty of loads with a small S60 and a Featherlite aluminium trailer.
It's been a few years since I last looked into it, but my recollection is that in Europe (or at least the UK) it is normal to balance the trailer to put less tongue weight on the hitch, which means you can tow a heavier trailer but have less stability at highway speeds (which they compensate for by having lower speed limits when towing). In the US typical trailer loading guidelines recommend putting more of the weight forward of the axle(s) for more tongue weight, which usually means the trailer will not sway even at speeds in excess of what the trailer tires are rated for.
In practice, a vehicle's safe towing capacity is usually not limited by the engine or drivetrain, but by the ability to stop the trailer safely. Brakes on the trailer itself help, but the big problem is that hard braking shifts more weight forward onto the hitch (trailer dive) and tends to lever the front wheels of the tow vehicle up, reducing their braking ability and in extreme cases eliminates your ability to steer while braking. A weight-distributing hitch counteracts this, but in the US light passenger vehicles are seldom rated for use with such a hitch. Towing at a lower speed also somewhat reduces this danger, by quadratically reducing the kinetic energy you need to shed in an emergency stop.
Not using your vehicles to the limit of it's capacity is one of the ways your signal that you're upper middle class.
Think of the stereotypes that plywood falling out of the bed of a 2010 Tacoma evokes vs the stereotypes that plywood strapped to the roof of a 2010 Crown Victoria evokes.
All countries in Europe except Germany have a general speed limit, most around 80mph. Towing a trailer has even lower speed limits, for example in Germany the max legal speed while towing a trailer of any size is 50mph, even on the Autobahn.
This in combination with beefier rear frames on euro car models (and no truck sales this would cannibalize) results in a higher towing capacity rating. It is much more common to have a utility trailer for the 3-4 times a year you would need it.
In reality people go up to 60-65mph with a decent trailer, that is about 100km/h.
I’ve been overtaken by a horsetailer doing a bit over 100mph. I do believe it was a Porsche suv doing the pulling tho. This was in Denmark.
Back when I was young and reckless my old Peugeot sedan was pretty stable doing around that speed with a flatbed dual axle trailer.
The horse trailer probably didn't contain a horse at the time. They're very useful for hauling all sorts of things, most of which are lighter than horses.
Here, you have someone who might move their single horse from summer pasture to winter pasture, and as a result, thinks that they "have" to have a HD3500 "dually".