So what these guys are saying would be in another words that if you are a pro (pro = making a living from betting) and you are living in the USA, you either live in Vegas or if not you bet exclusively using locals.
Otherwise it's impossible to make a living because all offshore books allow just longterm losers or small change long-term winners.
Is this true or not?
(I have another citizenship too besides American -a country from the EU, and I am fully using this in my betting, this is why I'm asking.)
Like I said I don't know much about local bookies in the USA, but most of the bookies offer -110/-110 lines.
If you really believe that a punter can make a profit for years and years betting on a -110/-110 line, then you could also believe that the Sports Almanac used on "Back to the Future" could be realistic too.
No professional punter would ever consider to bet at such lines and use such services.
Local bookies are made for gamblers, for people that have a gambling addiction, nothing else than that.
Of course Vegas offers way more chances in order to bet professionally regarding local and offshore, but still I wouldn't bet full time there.
According that you have EU citizenship, you should know that there are two countries that are the sports betting "paradise": One is Malta and one is England. On both countries sports betting is fully legal and it is TAX FREE. In Malta you can register to any .com world wide and in UK almost the same. (Unfortunately since 2014 Pinnaclesports is not available anymore in the UK, so Malta is the "paradise" of the pro right now.)