I honestly think what have been holding him back are his previous (or current?) contract owner (Sahamongkol Film?) and his own stubbornness. Jacky Chan invited him to join a movie with him not long after his movies Ong Bak and Tom Yam Kung but Jaa refused due to the offer was not for a leading role. Tony Jaa has been looking for a leading role in a bigger stage like Asia or Hollywood for a while but his contract with Sahamongkol Film disabled him from doing so. In my opinion, if he could, he should have accepted for any role in Hong Kong and anywhere and should not only expected for a leading role. He's a big name here in Thailand, but he has to start somewhere. Hopefully he might have a better chance to shine after taking part in this block buster.