This one was harder for me to answer. I can see 2 reasons:
1) Good relationship with third parties. It's quite clear developers wants Playstation systems to be a success. Sony designs their hardware based on what the industry and other publishers would likely want a Playstation hardware to be. From standardized controllers to certain level of computing power to process the newest graphics. Their relationship is good enough to secure even GTA VI being released on PS5 1 year before the PC release. Japanese developers kept their games exclusive on Playstation for as long financially viable. This speaks volume on what publishers think of Sony and Playstation
2) Taking every market with care (except Japan* where they decided to abandon when killed their portable line). Nintendo is dogshit when it comes to availability, distribution and pricing outside America, Europe and Japan. Microsoft is better but lacking in branding. But no company saw and treated Europe and ROW with the same care and importance as Sony. Playstation has currently 5/6 of the best selling consoles in ROW. Those markets loyalty has secured Sony long-term stability in console bussines, in the same way Japan secured stability for Nintendo's bussines
* I'm putting an asterisk here because even Japan was not dropped so deliberately. They moneyhated tons of Japanese third parties during PS4 life, it's just their efforts to cater Japan were unsuccessful. PS5 is where they really given up
