Digital DL's are the future. Apple's cloud, google's cloud, etc... This will also lower the cost due to burning millions of CD's, boxing, packaging, shipping.
Who cares about backwards compatibility? Once the new Xbox or PS comes out, the old ones will drop dramatically in price.
1 TB Hard Drives are cheap as hell now, even to end user consumers
As far as playing DVD's- there could be an external DVD drive. Microsoft sorta did this with the original Xbox- you needed a remote to play the DVDs.
Good to hear PS is going with AMD processors