The Giants, by the way, have contributed to their own revival. They let Dusty Baker go in 2002, sending him into the world, and he eventually wound up in Houston. Baker’s and Bochy’s World Series wins in back-to-back seasons have sparked a retro movement in baseball, a new appreciation for old-school skippers. The Giants joined the movement they accidentally helped start by bidding bye-bye to Kapler and saying hello to former A’s skipper Bob Melvin.

The A’s have been great for the Giants. The A’s Walter Haas ownership group helped the Giants stay in town in 1992, granting the Giants territorial rights to the South Bay.

The A’s did not get their deserved credit for the Giants’ hiring of Melvin. Had Fisher not decided to make the A’s into such a blazing trash fire of a franchise, Melvin would not have fled in terror two years ago with time left on his contract.

Fisher has been great for the Giants. In 1992, when the Giants were threatening to leave San Francisco, Fisher talked his dad, Donald Fisher, into joining a local group that bought the Giants and kept them from leaving. John’s part ownership in the Giants got him in the game, so he was ready to pounce when the A’s went up for sale in 2005.

Fisher was unsure whether he should buy the A’s, but his fellow Giants owners convinced him it would be a smart move. Thanks, fellas!

Had Fisher not been in the picture as a prospective A’s buyer, who would have bought the team? Well, Reggie Jackson claims he led a group that had the highest bid, but got kneecapped by then-Commissioner Bud Selig. Maybe so; there are differing versions of how or whether Jackson’s group got aced out.

Joe Lacob, now owner of the Golden State Warriors, claims he had a handshake deal to buy the A’s, a deal he says Selig killed because he wanted the team sold to his old college frat brother Lew Wolff, a minority partner to Fisher.

Had Lacob bought the A’s, they might have been in the World Series this year, bringing more hardware back to the Bay. Instead of the cheapest team owner in baseball, Oakland would have had one of the spendiest and smartest. Who knows, maybe Bochy would be their manager.

Had Lacob bought the A’s in 2005, it’s likely that when the Warriors went up for sale five years later, he would not have been in position to buy them. He would have been too busy and too financially extended from building the new A’s ballpark at Howard Terminal (minus the massive, preposterous mini-city that Fisher would later propose).

So Larry Ellison would have purchased the Warriors. While Lacob was busy reinventing the Oakland waterfront, Ellison would have been building the Coliseum site into a wonderland that would revitalize the Town.

However, it’s unlikely that Ellison would have stumbled into hiring Steve Kerr, as Lacob did. In 2014, Kerr would have taken the offer of his friend and mentor Phil Jackson to leave television and coach the New York Knicks.

Here’s one guess at how life would have unfolded for Kerr: He would not have taken those 2014-15 Knicks (who finished 17-65) to the NBA title. Kerr’s whole joy thing would have fallen flat in the Big Apple. Daily News headline: “Warriors 127, Joy 98.” A horse named Kerr’s Joy would have finished dead last in a claimer at Yonkers.

After two long seasons, Kerr would have had his fill of coaching, his lofty dreams dashed by reality. He would reject offers to go back to TV broadcasting, a career too limiting for a man of Kerr’s creativity and leadership.

Despite his failure with the Knicks, Kerr would have become a darling of fans and media in New York, and would have made high-powered political connections, who would ask him, Why try to fix another basketball team when you can fix the country?

I’m not qualified, Kerr would protest. Kerr’s new friends would tell him, Uh, have you seen this other made-in-New York pop/media celebrity with zero political experience and zero soul, who is planning to run for president?

Kerr would take one for the team, get into politics, work his way up, and right now he would be out on the campaign trail.

Sometimes the winds of fate blow badly.

Reach Scott Ostler: sostler@sfchronicle.com; Twitter: @scottostler