Opinions vary greatly on the whole Graf-Seles issue. I personally dont think the stabbing made nearly as much difference as some. Seles has never beaten Graf on a medium to faster surface and couldnt even do it pre stabbing. She was humiliated their lone meeting on a fast surface in the Wimbledon final, and even beaten up pretty badly on their only meeting on a medium surface in the U.S hardcourts final. So I dont see the likelihood of her beating Graf in a Wimbledon or U.S Open final much at all (Wimbledon virtually nothing). Graf only played and won 1 Australian Open after the stabbing and most other years missed with injury or played injured, so Seles potentially continuing general dominance there is virtually irrelevant to Graf.
That leaves the French Open. Graf did win 4 after the stabbing and Seles was dominating there. However I doubt very much Seles was going to win all 10 French Opens in the 90s, and considering Majoli and Sanchez (great player but owned badly by Seles) were the only other winners, Graf was probably going to have to win atleast a couple of those at some point anyway. Seles never IMO owned Graf whatsoever, she benefited in the early 90s from Graf being in a slump of form and very rarely even reaching the finals. They only played in 3 slam finals in the 2 and a half years before the stabbing.
Graf winning virtually every slam she played after the Seles stabbing means Seles would have to start truly dominating Graf head to head in a way she really hadnt to continue her pre stabbing streak, which IMO is unlikely. It is also not like she made such a strong extended return to the game even considering what she went through to merit alot of benefit of doubt if you are someone who is in doubt (which I as you can tell am to begin with). Keep in mind when she first returned to the tour people were predicting her to do alot more than she did. In the early 90s there were some very good players but few tough matchups for her, only Graf really who as I already illustrated she barely played, and to a lesser degree maybe Capriati on hard courts. Post stabbing years there was Graf more regularly in the finals of course, but also Davenport, Hingis, Serena, Venus. Maybe confronted with people who presented challenges to her game which an aging Navratilova, Sanchez Vicario, Capriati (a strictly B power hitter compared to Williams, Davenport, or Graf), or Sabatini could not, she just wasnt ever going to have the same degree of success.