Part of the trouble is that all their products are separate.
Say you buy the new Sony portable gaming device, the Vita. Can you read e-books on it from the Sony e-book store? Nope. Play games from the Sony Android store from their Tablets? Nope. Or vice-versa, can you play PS1 games you bought for your PS3 on your Sony phone or tablet? Nope (though I think you can buy them again from a different store)
Sony needs to work as one company, not dozens of them, with one Sony ecosystem. But they simply won't. The last CEO tried it, but couldn't get them to co-operate, and this one likely won't get them to do it either, even though he is a pretty sharp guy