Personally I dont see what is so different about a relationship with a TG or BG to a relationship with a Canadian, Aussie or Swiss girl. Granted there would be less need for money but if you have a fling with a 2 week Swiss chick and carry on the relationship via the phone/net is that any different. By the same token a western girl can easily have multiple boyfriends on the go remotely. With the FIFO (Fly In/Fly Out) workers in Perth I see this occasionally, not like they hide it from their friends, they brag about it for the most part. I used to work with a 20 something Aussie girl who had 4 FIFO boyfriends at once all buying her stuff, the entire office knew this, most of the time we knew which ones were in town at the time (especially since she kept the details in her Outlook calendar, which was open to the entire office).
Sponsorship works, for the relationships that work. There are more than a few examples on this board. In previous posts some have detailed their relationship with their wife or LT girl friend and I think they were good examples of how a relationship worked. The fact that money was sent was superfluous to this. I dont class these people as "sponsors", if they are "sponsoring" they typically understand that she may go with other customer.
The problem we have is that sponsors aren't getting into a proper relationship, rather they are agreeing to a financial transaction. I'm not a doom sayer but there are some that have deluded themselves into beleiving that the 20,000 B per month they send a lady is keeping them out of bars or away from Thai BF's. Put simply the layer of trust built in a proper relationship is not there. But these people are quite small in number and often wise up/run out of money in short order.