The fact that you can run linux on a ps3 was intended by Sony. But it doesn't allow you to play unauthorized games.
There are two reasons why modding is not going to work in the ps3:
1) The technical reasons as described above.
2) Games are becoming more and more online based. Added to that you often have to update the games as well as the ps3 online. With this factor, modding is made much more difficult, as with every update someone has to figure out a way to crack the update etc. Too cumbersome.