WWE Network: AJ Styles makes his WWE debut in the Royal Rumble Match: Royal Rumble 2016 www.youtube.com
We were all in shock when AJ Styles debuted in WWE back in 2016: it was a surprise from left field because he had been tearing it up in New Japan for a few years. To leave during his hot angle with Shinsuke Nakamura (who left for WWE the same time in 2016) was mind-boggling. However, his debut at Royal Rumble as the Number 3 entrant was the best thing about that pay-per-view. His initial rivalry with Chris Jericho showed that the company had their eye on Styles in a main event status, and by the time he got to Summerslam with John Cena, we were on the cusp of seeing him win the WWE title by years' end.
My point is: Styles has done everything in this business so if he wants to end his career after his contract ends, let him.
Not pointing any fingers or anything, but it's quite simple for one fan to say, "Oh no, not him. I want him to stay, he's my favorite." You have good reason, too: Styles is one of the best wrestlers in the world right now (go ahead and check out my previous article praising Styles here), so to see him go will be a sad day. Picture this, however: he's a 2x WWE champion, 3x US champion, and has had countless MOTY candidates under the WWE flag since his debut. Outside of WWE, he's held titles in Japan, TNA, and other promotions he's wrestled for. There's absolutely nothing else left for him to do in order to cement his legacy as one of the best wrestlers of the 2000s/2010s, as well as the greatest of all time.
His contract doesn't end anytime soon but we should enjoy what he does before he heads out into the sunset.
(If he goes to AEW, then that's a different story.)