As if silva's herrera's mata's and whole lots of other nationals dont have family's and girlfriends. Dont buy these arguments one bit.
All the players you mentioned above move outside Spain chasing a better pay...Don't get me wrong, if any of the players you said being offered by Real Madrid and Barca, there will be a different story...
Playing for best clubs in your country may have values higher rather than money. Pride among your family and friends, recognizable environment, same language, etc...
And why did Real and Barca not offer those players ?
1. May be because they are not good enough in term of technical ability and positional need. E.g : Between Silva and Villa, Barca picked Villa...because they had better midfielders at that time than Silva
2. May be because they are not marketable enough in term of commercial...Spain big clubs a little bit different with EPL clubs, they rely so much to Fan-based...
3. They player themselves perhaps, don't want to be only supporting casts if playing for Barca or Real.
DDG case is different with CR7.
CR7, despite of his dream to play for RM, also chasing a higher paid...I believe at the beginning that's the reason...
However, i believe that for CR7, who always fight for being no.1, time to time, he has found lots of challenges playing in La Liga with Real Madrid...Not just for being the Champion in the La Liga, but to be the best of the best in the world every year, in every aspects, broken all records existing...which sadly, he may not be able to achieve while in Man Utd.
I believe that CR7 also get a nice wage increase every new contract and perhaps he is being specialized/golden boy at Madrid. But with his contributions and his commercial value, the amount is returned to the club, with good margin too.
DDG, despite playing with one of the richest club in the world, with one of the greatest Manager ever in Fergie, at very homey city of Manchester, and with perhaps highest paycheck for the GK, still missing great achievements in his career. While, he is labelled one of the World Best Keeper individually, in term of Club Achievement, he only had a few. Perhaps, like Maslow Theory said, DDG needs self actualization. And tittles with the clubs is one of it. And I agree with some posters here that said about him wanting to start a family. He is human after all, he has his Girlfriend, both of them loyal to each other despite of LDR, so if he wants to start a family with her there's no wrong about it.
As long as we have the good fees, no need to be hate for his decision, if truth that he wants to leave.
DDG has given his best while playing here....millions of fans are the witnesses.