I think MT is failing because they only allow busiless in the US, which is a tiny market for jobs that pay pennies/hour. But if Amazon managed to open up say, India or China, there would be a much richer ecosystem in place.
An interesting finding is that it costs about $5K-10K to open a US bank account from overseas, post 9/11. Pre 9/11 it was probably around $100.
Although you can use MT credit to buy stuff out of the Amazon store.