This brings me to remember the many discussions here on whether we are tipping too little or not.
Case in point: I know several asian masseurs who, after a working a few years are able to put up businesses, finish college from good schools without incurring any student debt, live large and afford designer goods etc. They rack up around 8-9k on average each month, tax-free. This is not speculation, my masseur friends earn this much. They were even teasing me to just work in the spa instead of my office job that pays way less. So my 2 cents: yes, masseurs at spas are getting tipped way well enough.