PlayStation as a brand is over 25 years old at this point, but not many people have been able to pin-point exactly what makes Sony's platforms unique vs Nintendo and Microsoft's. It's easy to say that Sony and Microsoft are simply just clones of each other at this point, but that's actually not the case. For me, the difference between PlayStation and Xbox systems is that Sony focuses on the "Holistic" gaming experience. What do I mean by this? Well, each of the big three have their own approach to platforms and hardware that define their place in the gaming market.
Nintendo typically builds its platforms around unique core idea. Whether that be 3D gaming with the Nintendo 64, on the go gaming with the Game Boy, Motion Controls and Local Social interaction with the Wii, Dual Screens with the DS, Stereoscopic 3D with the 3DS, Asymmetrical gameplay with the Wii U, and Playing games anywhere with anyone with the Switch. All the features and hardware of Nintendo's systems are made to support that single core idea at every turn. While this helps Nintendo fill unique holes and needs in the market, it also often means their platforms tend to be less powerful and feature rich than the other two. Whether that's good or bad depends on how you see Nintendo in relation to Sony and Microsoft.
Microsoft with the Xbox line, focuses one concept, Power. While each of Nintendo's systems have its own unique concept, all the Xbox systems essentially have the same concept. Build the most graphically impressive gaming experience possible, for as affordable as possible. Xbox, Xbox 360, Xbox One X, and Xbox Series X are all designed around putting graphics at the forefront of the experience, with everything additional supporting that idea of delivering the best graphics for a home console. It give Xbox a leg up in terms of raw specs, but it also often means Microsoft can be behind in other aspects that come with a new console such the potential of new formats, or controller inputs.
With Sony? Ever since the first PlayStation, Sony has always focused on innovating the overall gaming experience, rather than simply graphics or new ways to play. The PlayStation wasn't just a powerful and easy to develop for 3D console, it was a 3D console that used the power of the CD format to deliver new kinds of presentation and worlds never before possible. Think about the long sprawling adventure that games like FFVII were, the high quality music provided by games like Parappa the Rapper, or even the Cartoon style presentation voice acting of Crash and Spyro. That's what you get when you think about innovation regarding the overall gaming experience. The PS2 built on that, not only being more powerful than the Dreamcast, but also having a DVD drive that allowed for bigger, more complex worlds, more cinematic presentation, pressure sensitive buttons, and a Camera that allowed for mixed reality gaming, which help innovate the overall gaming experience. The PS3 was built around its monstrous Cell Processor allowing for advanced physics, Blu-Ray format allowing for massive, HD worlds, Sixaxis and later PS Move allowing for intuitive motion controls. PS4 having an enhanced online community that you could share with friends, x86 making development easier and smoother, Touchpad and speaker adding a new layer of touch and sound to games, and the introduction of PSVR which allowed an affordable and immersive VR experience.
Rather than building their consoles around a singular idea like Nintendo and Microsoft, Sony instead designs each PlayStation around a variety of smaller ideas, that help innovate and elevate gaming to a new overall level. I think the PS5 is by far the best representation of that philosophy yet. 4K Blu-Ray, Fast SSD, Ray-Tracing, 3D Audio, DualSense haptics all help to create a more holistic innovation in gaming than Nintendo and Microsoft's approach.
I think that's why PlayStation has been around for so long, and why Sony consistently succeeds with each console. That isn't to say Nintendo and Microsoft's philosophies don't have merit, but I think Sony has always done the best job at looking at what can be innovated and improved on from a much wider perspective than the other two.