Of course it's hard to say how many he would have won, but it's not hard to say he would have won more. Rafole will most likely both end up in the top-5 or better all time. To have to contend with that kind of talent, when you yourself is out of your peak and prime years is tough. Edberg-Becker was more to illustrate that having two guys like Rafole chasing you is
not the natural order of things - that's an outlier because that kind of talent doesn't come around often.
And yes, it cuts both ways - hence why Novak had it tougher in his 19-25 period. Or 19-26 if you will. 27 onwards - not so much imo.
And yes, Novak could have won more in 2011-2014 if not for Fedalray, but as
@mike danny said, he really is expected to beat Murray in a slam final. He went 12-1 against him from Murray's surgery until Rome last year.
This is where we differ. I don't see why that should be the main point. Competition should be evaluated over the course of a career. Whether you had it tough early on or late on isn't that important for your overall slam haul. The main thing is this: Djoko was good enough to win slams before 2011, but didn't win much due to Fedal. Fed was good enough to win slams post AO 2010 for the main part, but rarely did due to Rafole.
Rafa pretty much won the slams he was good enough to win imo - he's had very few misses, but he's also gotten less often to the business end compared to Fedovic.
And yes, it's relevant that Rafa was on 9 slams already when Novak hit his peak in 2011. Up until that point, his main competition was Fed, who he had a big match up advantage against. In comparison, Fed was on 7 slams, when Rafa got his 2nd. And as for Fed having 12 by the end of 2007 (or 9 by the end of 2006, as Rafole both very clearly were factors in 07), then adding another 7 or 10 thereafter depending on where you make the cutoff, it better than what Rafa (so far) managed after he got another ATG rival, who didn't have a match up problem vs. him (6 slams so far after Novak hit his peak).