This happens in all sports. Pros are not allowed to enter amateur events. Probably something to do with them being pros and therefore, by definition. not allowed to enter amateur events. It's the difference between being a pro and being an amateur.
What they need is more pro events, run professionally with referees and rules conducive to professional play. Alternate break would clearly be one of those conducivish things that would make it professionalish and therefore likely to get some kind of sponsorship and some interest from those that are interested in the game beyond hooting and hollering about a once on a lifetime x-pack that omg we haven't seen since the last time.
How about this......we need more pro am events. A way both can play, and a good way for an amateur to mingle with the pros.