Phil Jackson will celebrate his three-year anniversary as Knicks president Saturday by flying to Los Angeles. The Knicks will practice there on Sunday and face the Clippers on Monday night. How poetic. Tony Bennett left his heart in San Francisco. Jackson left his basketball brains in La La Land. No longer engaged to Lakers president Jeanie Buss, Jackson still owns his Playa Del Rey beachhouse. He probably wishes he never had left the shores of the Pacific. Jackson’s best attribute as NBA history’s most decorated head coach was, according to his friends, “managing personalities.” He has not shown that knack as a team president. Just ask Carmelo Anthony. Jackson is not opting out of his contract or abandoning Team Titanic III. That’s the only compliment you can pay him regarding his three-year reign. He won’t quit. He won’t attend any NCAA Tournament games either, but is watching most of them on TV. He has deployed his army of scouts, and on Thursday, his phone didn’t stop beeping with their updates on this prospect and that one. The last and only time Jackson possessed a lottery pick as president, in 2015, he nailed it — Kristaps Porzingis. But that’s about all he nailed. On March 18, 2014, in his introductory press conference, Jackson promised to “develop a culture.” He has failed magnificently. His three full seasons as president have produced records of 17-65, 32-50 and now 27-42. Mr. “11 Rings’’ is 81 games under .500 — 76-157. Making the Reign of Zen — or “The Pain of Zen” — more disturbing is that Mike Woodson’s 2013-14 club finished out 16-5. Those Knicks missed the playoffs by one game. Then Jackson started changing everything — for the worse. Broadway’s rock bottom has no floor as the Zen Master enters another anniversary on the heels of two pummelings in five days by local rival and the NBA’s worst team, the Brooklyn Nets. As one scout said afterward, “The Nets have a worse record — the Knicks have a worse team.’’ This is a real New York tragedy — the popular former Knick defender who won two rings on their only championship teams returned as a demigod and wound up looking like a dunce.