Joe Torre walked when the Boss told him to run, which explains why the most successful Broadway couple this side of “The Producers” is officially kaput.

Blame whomever you want. It’s hard to say who underestimated whom.

There’s no way Torre was hanging around for the money, and whichever Steinbrenner came up with the idea to dangle a third of his salary from last year as a performance bonus this time around shouldn’t have been allowed anywhere near the negotiating table. Torre hardly needed motivating, and if the Boss & his boys had any intention of keeping him, insulting Torre was just plain dumb.

He just finished what might be his best managing job ever, which is saying something, since Torre won four World Series, six pennants and made the playoffs every one of the dozen seasons he worked in New York. The team he put on the field in April and May looked like it would have had a hard time qualifying for the Little League World Series, let alone the grown-up version.

The fact that Torre got the Yankees that far proves he still has it, all of it. He commanded respect in a clubhouse brimming with alpha males. He was revered by the veterans, and the kids he was bringing along know they’ll never get a better lesson in what it means to be a professional – no matter whether it’s Don Mattingly, Tony La Russa, Joe Girardi or somebody else who takes over their education.

The only thing Torre lost, maybe, was the stomach to prove it one more time. That’s too bad.

Remember how entertaining it was in the final season of Chicago’s crumbling NBA dynasty, when management let coach Phil Jackson know that he was walking the plank, and the Bulls won one final championship to stick it to the bosses? Well, it could have been like that in New York, only with more backbiting, bigger headlines and better tabloid coverage.

Mariano Rivera would almost certainly be back, provided the money is right. Maybe even A-Rod, too, so he could play the Michael Jordan role and finally win New York’s heart. Maybe Derek Jeter proposes to make up the difference in Torre’s deal out of his own pocket. Then ESPN embeds a camera crew with the team next season and we get “The Bronx is Burning: The Sequel.”

But no.

Instead, we get Hank Steinbrenner spouting off about winning for a few minutes Thursday on a conference call with reporters.

“The objective of the Yankees since the ’20s has been to win the championship every year, just as the objective of Lombardi with the Packers was or Belichick and the Patriots,” he said. “None of us think we can win the championship every year, but that’s the goal. Period.”

But Torre has forgotten more about winning championships than Hank ever is likely to learn. Every owner loves the phrase “October baseball,” especially when it’s accompanied by the tinkling of cash registers ringing. In fact, Hank’s old man probably should get royalties every time somebody introduces Reggie Jackson as “Mr. October.” But the game’s changed in some important ways since then.

Three rounds of playoffs means the hottest team in baseball wins, which is not always the same as the best one.

Torre’s genius was letting everyone do his job and taking the heat every time they didn’t. That combination of guts and grace is rare. The next generation of Steinbrenners is about to find out that it might be easier picking a pope than finding the right manager for Yankees. Especially since they just let one walk.