They have a dream in Oklahoma City, a surge of optimism shared by fans, players, executives, little kids and local merchants. It reveals their NBA team laying waste to the opposition on the strength of sheer superstardom.

Until further notice, it remains pure fantasy. And as the Warriors visit the Thunder in a much-anticipated matchup Wednesday night, the contrast between the two teams will be as glaring as ever.

By season’s end, it’s entirely possible that Russell Westbrook, Carmelo Anthony and Paul George will have meshed into a seamless unit, displaying all the fundamental tenets that define great teams — the Warriors, in other words. For the moment, this is a 7-9 team that can’t win the close games and hopes merely to make the playoffs, let alone dominate them.

From the moment they take the floor on a given night, things seem pretty dreamy. The Thunder’s style of play will never be confused with the Warriors’ sophisticated ball movement, but they take the time to at least set a screen or two, or find the occasional cutter, and they usually find themselves taking a big first-quarter lead. It was a 19-point edge in New Orleans on Monday night, before things fell apart in defeat and left OKC with an 0-7 record in games within three points in the last three minutes.

Old habits die hard. It’s simply not ingrained in Westbrook, Anthony or George to find the open man, because all three want to be that man, with long histories in that role. Make no mistake, Stephen Curry, Kevin Durant and Klay Thompson savor the thought of taking clutch shots; it’s just that they don’t give a damn about personal glory. They might pass up an open shot to find someone who’s even more open. That’s a very crucial difference, and you seldom see the Warriors standing around during any possession, let alone at crunch time.

“It’s not that easy to say, ‘Just move the ball, just cut,’” former NBA head coach Jeff Van Gundy said on Tuesday’s LowePost podcast. “Those are skills that come naturally to some players, but not to others. To expect (OKC’s) guys to dramatically change who they are, this late in their careers, I think is naive. They don’t find it easy to do those things. As a result, they’re not getting nearly enough layups. You can’t just base your game on jump shots.”

Durant’s status will be the primary story line Wednesday night, and perhaps we’ll see OKC’s latest version of a lame, small-town reaction to a onetime local hero returning as the villain. (Please, retire the cupcakes.) But that’s a tired story, and at some point, everybody just needs to move on.

Westbrook certainly thinks so, dismissing the notion of a “big game” with reporters after Tuesday’s practice. “Don’t matter who we have next,” he said. “It’s really about us.”

If head coach Billy Donovan’s recent strategy continues, the Warriors will see Westbrook, Anthony and George on the floor together for roughly the first six minutes and the last six minutes of each half. Andre Roberson will be a starter, and that’s when OKC is at its best on defense (impressively, the team ranks third in defensive efficiency). But Roberson is one of the worst shooters in the history of NBA guards. Donovan simply can’t afford to play him for long stretches at a time. Depth is a problem quite evident when one or two of the stars take a seat, and with Enes Kanter, Taj Gibson and Domantas Sabonis moving to other teams, the team’s rebounding has suffered.

There’s also the matter of who actually takes that big shot. Anthony’s 42.2 shooting percentage is the lowest of his career. The same goes for Westbrook (39.4), to go with his 32.5 from three-point range. Among active players, George holds the dubious distinction of taking the most game-tying or take-the-lead shots without a make (21) in the final 24 seconds of a game since 2010-11.

“We just communicate, man. We’re not worried about it,” Westbrook told reporters. “Whoever has it going, that’s where the ball’s going. We play off each other and figure it out. The game will tell you what to do.”

It’s hard to make a sensible decision, though, when “hero ball” becomes the prime mentality. “For 3½ quarters, they’re put together well,” ex-NBA guard Chauncey Billups said on ESPN. “But when the clutch time comes, that’s when the issues kick in. I’d like to see these guys get into some action, some pick-and-rolls with Westbrook and George or Melo. Find out a team’s deficiencies and attack that. Otherwise, teams are going to be ready for that isolation shot.”

Contrast: In the final three minutes of the Warriors’ victory in Brooklyn on Sunday, Durant was out with an injury and Curry had fouled out. So little was lost. Kevon Looney, who shares the Warriors’ schematic knowledge with all his rotation teammates, was an influential presence as the game was decided. And Thompson hit two big shots. Certain basic truths kicked in, calling up memories of every great team that had an infallible system in place.

Oklahoma City would love to get there, someday. Until then, dream on.

Bruce Jenkins is a San Francisco Chronicle columnist. Email: bjenkins@sfchronicle.com Twitter: @Bruce_Jenkins1