Barkley on 29 June 2017
They succeed because they create good hardware, they partner well with other developers, they have excellent marketing, and put a lot of effort in. They allow their first party's a good deal of freedom to make games that likely aren't going to sell several million.
The only PlayStation not to succeed, the Vita, seemed to lack any effort on Sony's part at all. They dropped support like a brick. Killzone Mercenary was the last big game they supported it with, and that was just 1.5 years into the systems life.
