I have a slightly different take on the PS4's success. Sony's strategy for the PS4 wasn't bad, but it wasn't exceptionally good either. To me it doesn't look terribly different than their PS3 strategy. People say that PS4 has great first party games like God of War, Uncharted and the Last of Us. Weren't these franchises also available on the PS3? But with the PS3, Sony lost money and now they are making money. What changed?
1) Sony launched at a lower price point for the PS4, $400 which helped them right from the start, compared to the PS3's $500/$600 launch price. And more importantly,
2) The PS4 had really crappy competition while the PS3 had really tough competition.
The PS3 launched a year after the XBox360 which was already doing decently in the marketplace. It also launched at the same time as the Wii which broke all sorts of sales records during its first 3 years on the market. I mean for anyone paying attention during generation 7, the PS3 was getting hammered from both sides. The Wii was topping the charts in both software and hardware while the Xbox360 had a much better online service and it often had a earlier release date for multiplatform games.
The PS4 did not have this kind of competition. You could see it right when these consoles were first presented at E3. The Wii U was stupid and the XB1 was evil. Both of the consoles looked repulsive to consumers. Then there was the PS4, reasonably priced and not offensive in any way like the other two consoles. Why wouldn't people want a PS4? It was the only decent choice available. Since then, the Wii U was retired early, while Microsoft seems to have mostly given up on the XB1 as well. The PS4 never really had any decent competition.
It's not Sony that really did anything different. It's Microsoft and Nintendo. The PS4 was so successful, because its competitors sucked.
Not as much a you think. On PS4 there was also the promise of great experiences (which was fulfilled) thanks to a few PS3 notable games like TLOU and people knew Sony would be giving great games until the very end like on PS3. And they are actually more than fulfilling that promise on PS4.
For reminder Micsosoft quickly abandoned to produce compelling content on XB360 , and Nintendo did the same with Wii and then Wii U.