No doubt Graf >> Seles on grass but that doesn't mean Seles would never have won there. That's a ridiculous assumption. Considering she was 23 and had already made the final.
Some Seles losses at Wimbledon post-injury:
In 1996, in her 4th Slam appearance since returning from injury (having already made 2 Slam finals and won 1 of them), Seles was seeded 2nd only behind Graf, and lost in the 2R to
unseeded Katarína Studeníková (7-5 5-7 6-4). The 'mighty' Studeníková then went on to beat an unseeded opponent in the 3rd round before losing 6-0 6-4 to an unseeded opponent in the 4R (that opponent ended up making the semi-finals). In short, Seles had a dream draw to at least make the semis (where she would've faced Sánchez Vicario), but could only manage a poor loss to not even someone who could be considered an average opponent (her highest ranking ever achieved was #31, she never made it past the 4R of any Slam, and her career w/l record was 75-85).
In 1997 Graf missed Wimbledon, so Seles was seeded 2nd. Her biggest opposition was Hingis (seeded 1st). How well did she do given such favourable circumstances for winning the title (remember, Hingis only ever made 1 Wimbledon final in her career, grass was her least favoured surface)? She lost in the 3R to
unseeded Sandrine Testud in 3 sets after winning the 1st set 6-0. Testud made 11 appearances at Wimbledon during her career, and only ever managed 3 x 3R wins: this was one of them. Further, in 46 total Slam appearances in her career, Testud only ever made 2 QF (lost both). In other words, it was a poor loss to an at best average opponent.
In 1998, Seles was seeded 6th @Wimby and lost to an
unseeded Natasha Zevreva in straight sets. This marked the only 1 of 4 Wimbledon QF that Zevreva ever won. Zevreva's best ever ranking was as high as #5, but that was achieved an entire a decade before this match took place (1989).
In 1999, Seles was seeded 4th and lost in straight sets (7-6 7-6) in the 3R to
unseeded Mirjana Lucic. In 11 Wimbledon appearances during her career, that is
the only 3R win Lucic ever managed. Further, in 45 total Slam appearance during her career, Lucic only ever won 3 x 3R matches. Lucic's highest ever ranking was #20, achieved almost 2 decades ahead of this match (2017). In short, this was another inexcusable loss to an average opponent.
All these horrible losses to unseeded players that prevented her from making then winning the final can be laid at the feet on an injury, while that same injury wasn't preventing her making 4 Slam finals and a further 4 Slam semi-finals on her more favoured Slam surfaces? That is, for me, the assumption that's ridiculous.
