This is simply not true, at least in the more densely populated parts of Norway. They are simply very expensive.
In the US, you can drive up and pay $1~/min and spray your car yourself w/ soap and water. You can also do the drive-thru option for about $10. On the upper end, you can pay $50~ for what might start as a drive-thru, but then someone comes out and does a manual touch up where the machine might have missed a spot, and then they will vacuum and wipe down the interior.
At $100+, you're looking at a hand wash and detail, potentially going up to hundreds of dollars for different aftercare options. Detailing can be very lucrative if you get a good referral network established.
It's also worth mentioning that you've jumped from menial to skilled labor at this point. There's a big difference between hosing off a Prius for the owner's commute and detailing a McLaren for an auto show. The latter is far more satisfying work.
Those polishing cars for auto shows are quite a bit in a different realm and not what’s being discussed here.
I agree that detailing supercars is a different league.
But yes, I doubt an American full-service car wash would recognizable in the Nordics.
And of course we have the kind where you wash the car yourself using a high pressure water jet in addition to the drive through kind (both those with and without brushes).
In the Nordics, there are no manual car washes, yet life goes on. Economically it doesn't make sense because of the high labor costs, and realistically it is a menial job that can be for the most part automated.
If you want to live in a world where you can have a cheap hand wash in your back yard, then you have to also admit to wanting structural inequalities to keep people trapped in those carwash jobs. It's delusional to believe that the people washing your car have a path out through hard work alone; my observation is that they already work pretty hard.
UBI is much more about giving workers power than giving them free money. And yes, there will be dole bludgers. Unfortunately any system is going to have inefficiencies, you just have to pick which ones and live with it. Alternatively, you can get tough on crime and house a prison population.