Nick
I don't disagree with you, but I also have dealt with our local "experts" to the extent that I know who is capable of what. When we have needed painting done, and please understand that I would rather do it myself than have the local guy do it, my lovely wife over-rules me and we have one of our previously successful painters do it, instead of me.
These guys have done, and will continue to do, excellent work for us. Yes, they are "jack of all", but who in the Thai villages isn't?.
We've been very lucky. I had the experience of new construction and remodeling work in the US for more than 30 years, and was fortunate to be able to see how Thai construction is done while our house was being built here in Thailand. Can I change it? Do I want to?
No...
But, If you want something done right and you know what right is, then give them a chance to do it right. They can and they will do a fine job for you, if given the chance.
I do know what you are saying, there are many folks that do more than what they should and more than what they know, but it only took us about 1000 years and they have been at it for more than 3000 years.
Yes?