Cubs president Theo Epstein didn’t hide his frustrations with an underachieving team hovering around .500, subtly calling out manager Joe Maddon in on-the-record group interviews, saying how the clubhouse didn’t play with enough edge and the answers would realistically have to come from the 25 guys already in the room.

But “The World’s Greatest Leader” — Fortune magazine’s call — doesn’t view things in absolutes. Epstein is always thinking three-dimensionally, analyzing the situation from 30,000 feet and never ruling anything out. Even when it looked like the organization-wide Cubbie envy would stop the White Sox from dealing one of their success stories to the North Side.

In a season where Epstein had already tried so many different forms of shock therapy with the defending World Series champs, the Cubs acquired Jose Quintana in Thursday’s stunning crosstown trade with the White Sox, trying to jumpstart a 43-45 team out of the All-Star break while still building their rotation for the future.

This is the price for a frontline starter, even one with a career losing record (50-54) and a 4.49 ERA this season: stud outfielder Eloy Jimenez; 100-mph right-hander Dylan Cease; plus Class-A infielders Matt Rose and Bryant Flete.

But all those prospects are years away from Wrigley Field, if they ever make it at all. Even Jimenez, a blue-chip talent with the size, approach and right-handed swing that reminded the Cubs of a young Kris Bryant, hadn’t made it to the Double-A level yet.

Quintana alone won’t fix the Cubs. It’s not like he will help them hit with runners in scoring position or tighten up the defense or heal all the nagging injuries that have contributed to the win-one, lose-one inconsistencies.

This does jolt the clubhouse, change the vibe around the team and give the 2017 Cubs an All-Star level pitcher for 14-ish starts.

[MORE: Why the Quintana trade makes perfect sense for everybody involved]

This is also insurance against Jake Arrieta and John Lackey leaving after this season. The Cubs dreaded the idea of having to replace at least 40 percent of their rotation this winter, knowing agents and other teams would sense the desperation.

As an added bonus, the Cubs will keep Quintana away from the Milwaukee Brewers, the first-place team they trail by 5.5 games in a National League Central race that just got a lot more interesting.

Ultimately, this is still a play for the future, with Quintana under club control through 2020 and the Cubs betting on his medical outlook and sturdy, reliable performance (at least 32 starts and 200 innings in each of the last four seasons).

Jimenez and Cease might become stars on the South Side as the White Sox methodically undergo a full-scale rebuild. But the Cubs are dealing from a surplus of position players and operating under the belief that young pitching goes poof.

The Cubs used money saved from Kyle Schwarber’s below-slot deal in the 2014 draft to give Cease a seven-figure bonus and supervise his recovery from Tommy John surgery, hoping the volume/risk-management approach would yield some trade chips and/or the homegrown starting pitcher that has eluded the Epstein administration.

It’s the same playbook the Cubs used in last summer’s blockbuster “If not now, when?” trade with the New York Yankees for Aroldis Chapman. And the winter-meetings deal with the Kansas City Royals for All-Star closer Wade Davis. Except Quintana is viewed as a long-term building block for the next great team in Wrigleyville, not a mercenary or a one-year guarantee.

The rush of adrenaline will eventually wear off after Quintana’s arrival, and the Cubs will find out if those answers really will come from within and when this World Series hangover will finally end.