pokoko on 09 April 2018
"Allow" isn't the right term at all. They would have to spend a lot of money for a team to reprogram all those games to work with the PS4. They have no incentive to do that, especially not this late in the life-cycle of the PS4.
Microsoft did it as a PR move because they were desperately trying to recover from the XO launch. Sony was never in that position and, to be quite honest, the fact that it didn't hinder PS4 sales probably indicates that it's not all that important to the average consumer. Sony going the Microsoft route at this point would likely do very little to increase unit sales.
If it was going to happen then it would have happened before now.
