20 years ago now the rule on B+E driving licences were introduced in the UK; as someone who was affected by it this meant I couldn't tow a trailer greater than 750kg unless the combination did not exceed 3500kg, and the trailer was not heavier than the vehicle towing it. Basically, this meant I couldn't tow some of the trailers I worked with, nor could I tow my parents caravan. I can tow however with L plates on, and with someone who has that endorsement on their licence - in some cases, someone who has never had any training, just got their licence before the 1st January 1997...
The knock on this is there is a problem with getting those in their 30's and under into caravan and camping holidays, and as there are a number of caravan manufacturers in the UK (there isn't the same Chinese import situation yet) this has a potential knock on on the employment in manufacturing - what has been happening is a period of innovation where caravans have got lighter in part to match the rules.
$2k would basically put it out of reach of many people - have a look at how much a MR licence costs to get, and that's probably going to be a similar cost to a trailer licensing scheme.