Why can't you buy some of the Beatles' songs actually sang by the Beatles on iTunes?

I have heard that its because Micheal Jackson bought out all their songs and now that he is dead his kids own them. If Micheal was still alive the songs might be available, but his kids are too young to make the decision to put the music back on iTunes.

But...I have also heard that it is because of licensing problems with Beatles Rock Band. So I really have no idea when and if the songs will come back to itunes. If you can sit and wait until they do though, go ahead, but it not, you can always buy the cds then upload them onto your computer.