& equally, I bet a lot of people spend a lot of money on their trip...perhaps more than just drive around self-contained - not everyone is a boy racer trying to clear it in 3 days!
DD stayed away 7 nights in hostels/B&Bs, mostly ate out (with 1 or 2 BBQs) - precisely the point for a tourist economy, surely?
My LEJoG earlier in the year was done with pretty well all accommodation and food being sourced along the way (okay, I'm not doing the NC500, but did head north from the Crask Inn then along the coast)
Or maybe it should all be sheep and local moonshine
Other pals of ours did it last year when things were released a bit, & certainly bought local things and ate out as well.
No doubt there will be a few ignorant folk matching your description, but I suspect most people touring anywhere are also keen to sample local stuff....