You sure? I swear Michu was called up to one of the squads last season? weren't spanish coaches pictured at swansea games watching him before hand? apologies if i got that wrong could have sworn he was though.
Mata plays in a different position to Thiago, its not really a worthy comparison, Mata is competing for 2 wide spots with the likes of Pedro, Silva, Carzola etc, Thiago would be competing with a declining and ageing Xabi Alonso and an ageing Xavi whos had fitness problems recently etc, theres far more chance for Thiago if things go his way than Mata.
But thats the point, hes been there fighting for 2 years since cesc showed up, and hes not getting the game time he wants, the situation hasnt changed, it dosnt matter how well thiago trains as soon as the big games come round and everyone's fit who does Vilanova pick? we all know who he picks, Xavi and Iniesta are 2 of the first names on the team sheet, how does Thiago prove himself when the only way he gets his chance to is if others are injured?? its easy to say stay and fight for your place but when your behind legends like Xavi your never fighting for the position so to speak, your just waiting in the wings if something goes wrong, you know thats true as well as i do.
From a fans point of view i totally get where your coming from, im sure youd love him to sit and wait and be there to take over when Xavi decides to call it a day, but for the player himself maybe he dosnt want to wait another 2 maybe 3 years for this to happen when he dosnt need to.