That's the question Jaime Diaz ponders at GolfDigest.com after the world No. 1 battled back at Royal County Down, only to be undone late in his round by a few slips.
He compares McIlroy's artistic temperament to Tom Weiskopf's as an explanation for the unusually high number of big scores he posts in competition.
Compared to the two dozen or so players golf's pantheon, at this point its fair to say that McIlroy's exhibits a distaste for grinding. Whereas Tiger Woods seemed to get as much satisfaction from turning a 75 into a 70 as from posting a 65, and Jack Nicklaus was a disciplined master of not shooting himself out of tournaments with wasted strokes, McIlroy models those behaviors almost grudgingly.
Not that McIlroy is a quitter in any sense of the word. He has dug deep when his game has been off on plenty of occasions, most notably last year in the final round of the PGA Championship at Valhalla. But such is his emergency mode, not his habit.
Ergo, the occasional missed cut, and the odd 80. Especially at a non-major, McIlroy when struggling in the first or second round is akin to a tennis player giving away the first set after getting down 4-0. In moments of weakness he may be susceptible to the Weiskopf reaction. The other variable that could be playing a growing role are the demands of being No. 1. While it's clear McIlroy enjoys that station and will fight hard to keep it, the mental burdens can be draining, and conserving energy may be more on his mind than ever.
Long term, the grinder mentality Diaz raises is a valid one and the wild swings in scoring may be something we just accept is part of McIlroy's swing and playing style. The bounce-back ability McIlroy has exhibited appears unprecedented, making his crashes less alarming than with other players.
But there is also the fascinating issue of his recurring issues with links-style conditions given his country of origin. Whether it's a lack of patience for wind, or firm and fast conditions, or simply finding himself more comfortable on lush, tree-lined courses instead of exposed ones, McIlroy now faces three straight majors at courses potentially presenting the conditions he is unaccustomed to liking and for which he managed to like enough to win last year at a soft-ish Hoylake.
Should he devote even more of his time to figuring out how to conquer such conditions? Or look beyond 2015 and accept that not enough significant tournaments beyond the Irish, Scottish and Open Championships are played in links conditions to warrant a reconsideration of his approach?
Historically, few of the all-time greats have gone an entire career having a chilly relationship with links golf. Bobby Jones and Tom Watson famously disliked exposed golf and unpredictable conditions only to become the most eloquent of all links spokesmen. Arnold Palmer, Jack Nicklaus and Tiger Woods were on board from the start and reaped rewards. Phil Mickelson always knew he should love the creativity and artistry required in links play but it took him nearly a quarter of a century to finally conquer such conditions. The payoff, however, forever changed his place in the history of the game from elite player to one of the all-time greats.
Ultimately, to be viewed as one of the very best who ever played, McIlroy has to at least figure out a way to get around such courses efficiently enough to not take his obviously superior game out of weekend contention. He doesn't have to fall in love with exposed golf, but if history is any indication, it would help if he found a way.
However, for fans of golf history, McIlroy's emotional and physical struggle to overcome this one weakness will be especially fascinating to observe in the coming years.