Actually, I thought that it led Mac strategically astray in the last half of his career....at least until the 90 USO.
He got it in his head, that he needed to fight power with power. He wanted to become a more conventional player!
He lost a step, he was into drugs to some degree, he had personal problems, injury problems....and he looked around and saw the players beating him were power players..
At one point around 88 he openly stated that his goal was to hit with 5-10% the power of Lendl and Becker, and then on top of it have his touch....that he or another player who could do that would be the ultimate player (sampras?). But I think he forgot how effective his game could be...against power or anything else. He was NEVER the hardest hitter...though he could ALWAYS generate enough sting, off his serve and groundtrokes at key moments.
I remember when he had a resurgence at the 90 USO...I think Vitas mentioned that.....that Mac rediscovered the effectiveness of his old game. Mac had gone back to an early coach and asked him what he thought of his game, and had been told "John, you're missing shots you never missed when you were 12!" The thing about John's highwire, touchy/feely ground and volley game, is that you must be CONFIDENT....there's a reason why nobody else could take on the rise power shots, absorb the power, and massage them back in various ways, redirecting them around the court to open up angles of attack.....it's HARD to do!
I think he forgot that he used to handle Lendl (Lendl DIDN"T suddenly get more powerful from say 85-86)....and even the post-burnout Mac of the later 80's was at least, giving Becker some tough battles. John got obsessed with trying to match these guys at their own game...a losing proposition. If Mac tried to play them more directly, more straight forward, hitting harder off the ground....all he'd do is have a more powerful looking loss!