I don’t think that Nike making crap clubs is the problem. At the pro’s level a little change that doesn’t feel right can be the difference between winning and losing.
I come from a tennis background and the difference between what’s sold in the shops and what the players use is unbelievable. For example, Roger Federer plays with a 90 square inch Pro Staff 6.0 painted to look like whatever the latest version being sold is. The racket he plays with is a mold that has been around since Sampras was a junior, so going back 20 years now. It also has a slightly different string pattern to suit his play. You cannot buy it in a shop.
If Rory is playing with off the shelf clubs then fair play to him. The tennis marketing is pretty duplicitous because they never acknowledge that the pro rackets are custom jobs. However, if you’re stupid enough to believe buying Federer’s racket will let you play like him then you deserve what you get. If results don’t come through then you will probably see him renege on the contract, or paint his old clubs or whatever.
A similar thing happened with Phillippousis when he swapped rackets (to Dunlop I think?). His results went down the drain. Soon afterwards he was playing with his old frames painted black.