If this continues and Matchroom gets a near monopoly on the best players ...
1) the WPA's hand will be forced in everything but Heyball, which I'm still not convinced has anything to do with pro pool.
2) WPAs choice will be to strictly enforce the edicts of Qatar and continue their events with mediocre fields or to back down and allow Matchroom players entry into such events. The most likely scenario to me would be that they will back down.
In this scenario, Matchroom would hold all the cards and WPA would likely either a) reconcile with Matchroom, giving Matchroom absolutely everything they want, b) abandon the policy of banning Matchroom players, or both of these.
WPA has helped to build pool's infrastructure worldwide and they can and will continue to do so, but at pro level, they'd play second fiddle to Matchroom, just as many of us want. As Justnum points out, the WPA has done a lot for women's pro pool and will likely continue to do so.
WPA can remain a very positive force in our sport, but they'll no longer be able to bully the organization that is pool's greatest hope for growth in over twenty years.