Then there were the naysayers who declared that any new schedule calling for back-to-backs and even back-to-back-to-backs would be too much of a challenge for teams whose primary players were born in the 1970s.

Who among us thought there even would be a Year 4 for this core group, let alone a Year 5? There would be a three-year window for Big Three II; isn’t that what we all thought? With needed help from seasoned auxiliary players James Posey, Eddie House, and P.J. Brown, plus the rapid development of Rajon Rondo into a major point guard force, they brought home championship No. 17 in Year 1, giving local fans one of the truly great seasons in the Celtics’ storied history.

They all will take to their graves the knowledge that no other Celtics team played as consistently hard from start to finish as theirs did in 2007-08, and it’s reasonable to assume that, if asked on their deathbeds to recall the final score of the final game against the Lakers, a smile will come across each and every one of the faces as they whisper, “131-92.”

Everything about that season brings back happy memories, but it’s all every bit as much a part of Celtics history as anything accomplished by Messrs. Russell, Cousy, Havlicek, Cowens, Bird, McHale, and Parish. It’s past. It’s done. It’s over.

Kevin Garnett, Ray Allen, and Paul Pierce are still here, but time inevitably marches on, and the last time we saw them on the court, they were incapable of stopping Miami’s own Big Three when it mattered. Regular-season mastery meant nothing as LeBron James, Dwyane Wade, and Chris Bosh combined to score 164 of the Heat’s 195 points in Games 4 and 5 of a five-game Miami playoff triumph.

We need to know if Danny Ainge had a long-range plan to handle the aging of the Big Three, and if it already has been altered. He is in the same position the late Dave Gavitt was in 20 years ago, and we all know how that turned out. Larry Bird’s back went out first. Then it was Kevin McHale’s lower extremities. And that left Robert Parish, The Chief, to go it alone.

There were flashback nights for each of them, and when those nights coincided, the Celtics were still a force. But they lost to the younger Knicks in 1990, the younger Pistons in 1991, the younger Cavaliers in 1992, and the younger Hornets in 1993 before missing the playoffs in seven of the next eight years.

The frustrating thing about being an aging player is that some nights it’s still there, and someone can be deluded into thinking nothing has changed. But it is not there with the regularity that made someone a star.

Allen and Garnett each have reached that stage. As an example, two years ago, Allen went from setting a record for 3-pointers against the Lakers one night to an 0-fer the very next game. Last May, KG went from a killer 28-point, marauder-on-defense Game 3 against the Heat to Just Another Guy status in the remaining two games.

Granted, there was another major factor in that series loss to the Heat. Rondo was playing with a badly impaired shoulder, doing so on nothing but guts and instinct. The Celtics lost Game 4 in OT and, despite all their problems, carried a lead into the fourth quarter of Game 5.

Ainge’s first major task is to construct a roster. Last I heard, he had seven players under contract: Pierce, Garnett, Allen, Rondo, Jermaine O’Neal, Jeff Green, and Avery Bradley. An eighth man would be first-round draft choice JaJuan Johnson, the slender 6-foot-10-inch inside-outside threat from Purdue. A ninth could be second-round pick E’Twaun Moore, a guard who also comes from Purdue, but that’s no lock.

Glen Davis is a free agent, and my guess is that Ainge will let Baby see what’s out there. There’s always a chance someone will be a big enough Baby fan to overpay him. If not, the Celtics probably would welcome him back on their terms. Then again, there’s enough drama surrounding him that the Celtics may already have decided enough is enough. Baby keeps assuring us that he’s “maturing,” but I’m not sure Doc Rivers is completely buying it.

Given the unavoidable age factor - find another team that plans on starting four players 33 or older - the Celtics will need major contributions from some guys with young legs. Rondo, of course, is a given. The next guy up is Green, who has a long way to go if he’s going to keep me from looking utterly foolish by having proclaimed that he was the best player changing sides in the controversial deal with Oklahoma City. (Granted, that’s probably not one of his major motivations.) I still think Green can help this team in many ways, and you have to believe the Celtics’ brain trust does, too.

Let’s say they max out. Let’s say the old guys stay reasonably healthy. Let’s say Green actually does produce and Rondo remains Rondo. Let’s even give them help from an unexpected source.

Is this a playoff team? Yes. But is it a true contender? No. There will be nights when their fans will love them, but there also will be nights when their fans will fear for them. The overwhelming odds are that, if this core group stays intact, the season will end with a playoff loss to yet another younger, fresher team.

However ...

Danny Ainge runs this team, and if there is one thing we know about Danny Ainge is that he will take risks. He knows what happened to the franchise when Gavitt allowed nature to take its course, and it’s difficult for me to believe he will follow that same path.

Garnett makes far too much money to be attractive to anybody. Don’t we all agree that Pierce is on his way to being becoming a Celtic lifer? So that leaves Allen, who still has great value and who could be the missing piece of the puzzle for many teams.

The lockout gave Danny even more time to think. He will do something. It’s inevitable.

Bob Ryan is a Globe columnist and host of Globe 10.0 on Boston.com. He can be reached at ryan@globe.com.