Because until someone else showed they could do with the Miami Heat what he did in 2006, driving it to the finish line with a supporting cast every bit as suspect as the current rendition, there would be a question of whether Riley was still the best man for the coaching job.
That moment might be at hand, with the Heat one victory from validating Riley as personnel maven, just as those Lakers titles decades ago validated him as broadcaster-turned-sideline-savant.
Today, Erik Spoelstra remains boyish coach, able to avoid shaving on off days and still capable of coming off as clean shaven for those incessant podium sessions.
But with a championship, Spoelstra will give Riley the luxury not only of settling comfortably into coaching retirement, but also, unlike his 2005-'06 coaching comeback, comfortably able to stay there.
It's a moment that in so many ways would be liberating for Riley, allowed him finally to flash that AARP card without the threat of future early mornings on frigid tarmacs in Minnesota and Salt Lake, wondering if the hip transplant will hold.
To a degree, that's what makes this moment nearly as significant to Riley as to LeBron James, albeit for far different reasons.
Riley wants to be done. But he knows it only happens with a championship finish for Spoelstra, just as he had seized the championship reins in Los Angeles from Paul Westhead and Bill Sharman.
He wants it to be enough.
And that's the thing. He knows he can be truly done only when this job is done, when LeBron James, Dwyane Wade and Chris Bosh receive the very type of ring he flashed in front of them all during 2010 free agency.
"It's a different time," he said. "I mean, I was the most blessed coach of all of them. I was. I had the greatest players with the Lakers, in New York great players in Patrick Ewing and John Starks and Charles Oakley. Came down here with Alonzo Mourning, Tim Hardaway, Caron Butler, Dwyane Wade, Shaquille O'Neal. I've been truly blessed, so I don't want to push myself and go back. I don't really have that kind of desire."
He is almost sated. From his third-row seat opposite the Heat bench, coaching closure could be at hand, knowing a return, or at least the possibility of a return, would no longer have to be in play.
And yet, this would not be a case of Riley fading away.
Not now, not while Phil Jackson is retaining relevance with interviews chiding the very likes of Riley, speaking of how he could not see himself working for Riley, but could yet deal with it the other way around.
In some respects, Riley refuses to age, even while acknowledging during a Tuesday photo session that further attempts to hide the gray are now futile.
He still is as feisty at 67 as when he was ranting on sidelines just four years ago and four decades ago.
It's just that he now chooses different battles, not necessarily with players or referees, but with the very evolution, or proposed evolution, of the game itself.
"The game is better than it's ever been, and I just hope they don't take the charge out of the game," he said of David Stern's latest pet cause. "I know the commissioner has become an expert on flopping, so I don't want them flopping back and forth on this issue when it comes to taking the hit somewhere here."
Because that remains who he is, still seeing the game through a prism where the Anthony Masons, Charles Oakleys, Bruce Bowens can be difference-makers, just as Shane Battier and Udonis Haslem, minimal-statistic, big-heart players, are for this current Heat team.
He's still the street tough from Schenectady, the Rupp Runt who jumped center at Kentucky at 6-foot-4 because someone had to.
But no matter where it ends, as long as it ends better than it did last season against Dallas, he will stand proudly alongside an owner who made him the franchise focus in 1995 and has demanded only one thing since, championship contention.
He delivered in 2006. He is about to deliver again.
And when he does, assuming it is imminent, it will make it even clearer that for all of the legacy built upon the success of Magic, Kareem, Worthy, Coop and Scott, that the ultimate legacy may eventually be not of the early success on the left coast, but the perseverance on the right coast, where no one had previously won until he arrived.
Showtime defined Pat Riley.
But this time, this moment, soon may complete him.
He is about to do for Erik Spoelstra what Magic, Kareem, Worthy, Coop and Scott did for him, make him a champion able to stand on his own.
Ira Winderman writes regularly for NBCSports.com and covers the Heat and the NBA for the South Florida Sun-Sentinel. You can follow him on Twitter at http://twitter.com/IraHeatBeat.