I think that has more to do with Crosby not wanting to play with Hornqvist.
Sheary-Sid-Horny was murdering the league last year. Helped Sid get another Rocket.
I don't think we see that next year though for any significant amount of time no matter how much I want to.
I guess I have to preface that I don't have a beef against Horny before I say the following, primarily because last I said it there seemed to be quite a loud fanclub that took any opposing viewpoint to their own as an unfair slight against him worth condemning. I'm simply offering my research of the quoted claim.
With that said, the above claim was not entirely factual at the time, at least the attributing significant credit to Sid's wingers bit. The analytics at the time were pretty favorable for that combo, which makes sense because they're both good wingers, but I watched with my own eyes every replay of Sid's first 30ish goals at the time when I was trying to come up with my own opinion on the matter. When his wingers were shifting between Sheary, Horny, Hags, and Wilson. The amount of 5v5 goals I was willing to give Horny specifically for instance direct credit for helping create (meaning he was directly involved in setting up the goal, whether it be the crucial pass or screen) was about 5-7 of those early season goals. The rest came on the powerplay or when Hagelin or Wilson was playing there. If you won't take my word for it go watch the highlights on the Pens site yourself. Some really seemed to want to attribute Sid's goal scoring pace primarily to Hornqvist or Sheary, and the actual in game footage just didn't match up with the staunchness of that belief.
That's not to say he's not a valuable part of the team like some will inevitably take from the above for whatever reason, but attributing Crosby's unsustainable pace to either of his wingers at the time is disingenuous at best. When they weren't coming on the powerplay, a good number of them were scored almost entirely due to Crosby's own individual effort, whether they be shots off the goalie's back or deflections in tight. Goals that would not have happened without Crosby primarily creating the scoring chance himself, regardless of who was on his wing at the time.
About the only combo I'd be confident in having real potential to replicate similar goal scoring success if it's at all controllable and not a string of fortuitous bounces, is Guentzel playing with him, as he's capable of playmaking independent of whoever else is on his line and thus can create for Crosby and not just primarily rely on him (he's a natural center so it makes sense). This compared to Horny who while providing his own unique contributions to a line that benefit his linemates, is undeniably more reliant on others to create scoring chances than not.
If this is what Crosby has an issue with (if the assumed is true) and he desires a winger with more individual creativity, short of requesting Kunitz be reacquired from Tampa I'm not about to state definitively he's wrong in that preference.