Very enjoyable post. One thing I'd like to mention is that Sony did enter one very experimental area with VR which I'm very proud of them about.
As far as direct competition, to me it's plainly microsoft. As a budget gamer, If I go on to eBay to buy a console, to play xyz multiplat: I can get a PS4 Slim with it's exclusives and massive support, or I can buy a sexy white Xbox One S at half the price. Obviously it's discounted because it isn't selling well. And I say sexy because I like my consoles looking like a storm trooper. But nothing else on the market competes with PS4 on the mass scale. Only PC has the multiplatform games.. but it's going to cost way more than a $150 used system.
Other companies like to fake to news and investors about plans to enter the console wars, they generally to get off the ground. Only microsoft has been able to actually enter and that's because they're microsoft. Plus, MS can get up the next round and go again. People like to say that it's impossible for them to hit a home run but that's totally not true. It can happen. Not saying it's going to, but it can.