Twelve straight seasons that resulted in a trip to the Playoffs came to an end last night, as the Mavericks were officially eliminated from postseason contention. Owner Mark Cuban, with an eye toward free agency, promises that Dallas will come back next year and be a better team. Per ESPN: “This is unfamiliar, uncomfortable territory for Mark Cuban. It’s the first full season of his ownership tenure in which the Dallas Mavericks are finished before the playoffs. He hopes it will be the last such season. ‘I’ve always said there is one winner and 29 other teams tied for last,’ Cuban said via email Thursday morning, hours after the Mavs were officially eliminated, ending a 12-year playoff streak. ‘Our goal is to win championships, so it’s disappointing to not win. But we will come back and get better next year.’ This is, as Dirk Nowitzki has said dozens of times as Dallas’ dozen-year playoff streak neared its end, a big summer for the Mavs. So was last summer, but they had to settle for essentially constructing a temporary supporting cast of players on expiring contracts or willing to sign one-year deals. That definitely wasn’t the plan when Cuban made the difficult post-lockout decision to let Tyson Chandler and other key championship pieces depart Dallas via free agency. The ideal situation would be adding a superstar who could take the burden off soon-to-be-35-year-old Nowitzki. When the Mavs opted to create significant salary cap space for the first time in the Cuban era, they did so with the belief that Chris Paul, Dwight Howard and Deron Williams would all be on the market last summer. [...] ‘Trust me, we want to do that,’ Cuban said Wednesday evening, referring to giving Nowitzki a legitimate co-star. ‘If you’ve got the guy who’s going to say, ‘You know what, I’m going to come to the Mavericks no matter what,’ let me know.’ The only promise Cuban can make about this summer: ‘We’re going to be opportunistic and do the best we can.’”