We can argue all day long about whether or not the NBA is “what it used to be.”

Athletes evolve. Styles of play and behavior change. And most of us profess a preference for the sports, music, television, politics, etc., with which we grew up.

To wit, I watched more professional hoop when I was a kid wanting to stay up past my bedtime than I do now. I’m more of a wake-me-up-when-the-playoffs-start fan today, which is still ample exposure for drawing conclusions and making comparisons.

It doesn’t take long for me to discern the biggest difference between then and now: Coaching matters substantially more in 2018. The ongoing run by the freshman and junior varsity version of the Boston Celtics is Exhibits A, B and C.

If the hype is to be believed (and let the record show I’m not necessarily a subscriber), the C’s had no business beating the Milwaukee Bucks and surely have performed far over their heads while snagging a 3-0 series lead over the Philadelphia 76ers.

Both opponents were touted as having the best player on the court, as if that’s an indicator of anything. The latter, despite the Celtics and Toronto Raptors seeded above and the LeBron James-led Cleveland Cavaliers having shown only a scintilla of interest in the regular season beneath, have been repeatedly bestowed the courageous, made-for-TV title of “maybe the favorite in the East.”

Yet here we are, with the whole laughably outperforming the sum of the parts in green. Clearly we’re learning that Jayson Tatum continues to be undersold as a future superstar. Likewise, Terry Rozier, Al Horford and Marcus Smart don’t receive the individual respect they’ve earned from the people who cover this stuff every day for a living.

Still, this team that was expected to revolve around the long-since-sidelined Kyrie Irving and Gordon Hayward has no business being here. When all other explanations fail, it has to be the coaching.

I’ll resist the temptation to throw out something hyperbolic and stupid, such as that Brad Stevens is somehow the greatest of all time, or even the No. 1 coach in the game right now without a ring to back it up. But if you would choose anyone else on the planet to coach your team for the next 20 years, you simply aren’t paying attention.

Stevens is not merely the right guy for this team, right now. He has the ideal demeanor, leadership skills and coaching acumen for this era, period.

Through most of my lifetime, the NBA coach was the classic warm body or babysitter from central casting. No offense to Bill Fitch, K.C. Jones or Doc Rivers, all of whom won rings in Boston, but they were not vintage X’s and O’s guys. Their lack of matching success at other stops on the coaching carousel is a reminder of their primary job description with the Celtics: Maintain some semblance of order, but ultimately get the heck out of the way and let stars be stars.

Even the purportedly great Pat Riley, Phil Jackson and Chuck Daly, who won the vast majority of remaining rings over a two-decade span, were star-driven and hand-picked. They were government by the people and for the people. They were the disciplinary figurehead Magic Johnson, Michael Jordan and Isiah Thomas chose to tolerate.

More than any other major professional sports entity, the NBA has perennially erred on the side of putting former players in charge. Lord help us, that’s how the Celtics ended up promoting M.L. Carr, in all his rah-rah, towel-waving, perpetually smiling glory. Steve Kerr of the Warriors and Tyronn Lee of the Cavaliers are a throwback to that philosophy.

These days, those guys have a low ceiling and a short shelf life. Gregg Popovich of the Spurs threw down the dunk, and you can give an assist to the NFL and the Patriots’ Bill Belichick. Their five rings apiece are evidence that your best option in modern times is probably a guy whose playing career ended in college or sooner.

Why is that the case in the NBA? The average age of your starting lineup is significantly lower than it was at century’s end. There is also a decidedly thicker international flavor. Your ability to communicate, reach young people and deal with diverse personalities and cultures is more important than ever.

Yes, in other words, Rick Pitino and John Calipari were ahead of their time. Both would have enjoyed much greater success in the NBA if they were 40-something and making that transition today.

I’m mostly talking about macro issues here, but Stevens’ eye for detail shines through in the micro, as well. His team makes plays at the end of games because they are impeccably prepared and in the right place at the right time. He uses his timeouts brilliantly, and the Celtics piggyback them with a basket nine times out of 10.

Of course, coaches ultimately are measured by championships, so don’t clear a space in the upper room at Springfield just yet. Getting Butler to the NCAA final in back-to-back years was a colossal feat, as is making the Celtics relevant and legitimate during the LeBron era. When there are 17 banners hanging from the ceiling in your office, nothing less shall suffice.

For now, though, I’m comfortable believing that the chances Brad Stevens is the guy who will help deliver 18, 19 and 20 are pretty solid.

— Kalle Oakes spent 27 years in the Sun Journal sports department. He is now sports editor of the Georgetown (Kentucky) News-Graphic. Stay in touch with him by email at kaloakes1972@yahoo.com or on Twitter @oaksie72.