I know they have some people like that but in the nicer more expensive restaurants seems mostly 30 /40 year olds spending freely. With nice motorbikes etc. Many booomers have a fascination with money and not spending it again just an observation.
in Chiang Mai at least most of the nice cafes, restaurant, bars are frequented by digital nomad types spending plenty of cash. Makes sense to let them stay here longer and for easier.
You can live in Thailand for 6 months easily without proper visa. If you’re new to Thailand it’s common to do this. You can do land border crossings twice a year (Jan-jan). I’d come and enjoy yourself for a few months then do the long term visa.