The Thais have a very different attitude to foreigners spending money
over there vs when foreigners are "stealing" money from the locals. Your definition of "stealing" will differ very greatly from that of the locals!....and the opportunity to make money from your activities may also differ!
Having said all that, plenty of foreigners do run businesses in Thailand, some even make money....well, so the rumour goes! The key being to already know your way around, including (especially) people. And having ready access to a big stick - whether legally or not. IMO preferably both......and that people you are dealing with know that you are not a(nother!) gormless Farang with more money than sense.
I second the caution on basing your business around a local female, well not to the extent that you don't have a plan B....and don't forget that the Thais can often be shortsighted on the benefits of any financial / business arrangements, a one off $100 this week or $1000 next year - and every year thereafter? Next year might not arrive (and is a long time in the future! - "want it now" is not simply a Western thing!), $100 is now......and in Thailand that is not
such a daft attitude to take.
Not sure if applicable to Thailand, but could be possible to set up in Malaysia
and run Charters through Thailand - whether one can pick up / drop off Punters in Thailand is another thing.