Think there's positives and negatives to going download only.
Pros:
Can't break the game
Games don't take up that much space considering you can buy 1Tb HDD for next to nothing
Convenience
Developer get more of the income from sales
Cons:
No 2nd hand Market
No physical copy
Can't lend games to from friends, or rent.
Could take a lot longer for games to come down in price.
Less competitive prices.
Will suck for those with slow connections.