It was huge that he made the cut and played as well as he did. It mad the haters and the stans happy. The haters liked that he didn't do well and the stans loved it because he played relatively well all four days. CBS and ESPN had to be loving all the extra viewers that came from watching him.
As for winning future majors, I think he's done. The bum knee was bad enough but the leg injury is much worse. Not to mention he's pushing 50. Nicklaus won the Masters at 46 and Watson almost won the British at 59. And those are the two (relatively) easiest majors to score well at. Even without those injuries, winning a major in your late 40s is double tough. The networks and the PGA need to figure out what to do when he's not playing full time. IS he going to play the regular tour after 50 or will he go to the Champions tour? Is his body going to be able to withstand the semi-weekly pounding of either tour? Could be he just plays in the majors, a select few events and silly season stuff. That might be the best thing for him and every other party. He avoids the grind of the tour and gets to play in the important events and the made for TV stuff which only lasts one day. When he does play it's going to be like the Masters and be seen as a special event. Watching him finish 45th at the Jabroni Open every week is going to take a lot of the luster off of him and his legacy. He certainly doesn't need the money. His son seems to be interested in playing. He can mentor him and play in 6-7 events a year.