This is reddit so nuance will be lost in most conversations, but the fact is OKC has built a new arena roughly every 30 years dating to before the Thunder ever existed. The main issue is the Thunder did not even ask, this is something OKC needs to do anyways because their market is dwindling in the concert industry because Tulsa, Wichita, Kansas City, and Dallas all have larger, newer, and better venues and OKC is losing economic impact to these other cities. This is not ALL about the Thunder, they are impacted by the decision dont get me wrong, but this is something OKC has done historically dating back to the 30’s to stay competitive in the entertainment industry. It is also going to be funded without a tax increase as it part of MAPS which has been implemented for the last 30 years, which was the source of funding for the current Paycom Center.
Since Tulsa built the BOK center they have been getting the majority of top tier performing acts over OKC. Oklahoma has never had have much in the way of entertainment which makes the larger events even more competitive. Why go to OKC if Tulsa has a bigger, newer, and more accessible venue especially if you are only planning one stop in this part of the country. That is why it is being built, and the Thunder want to lease the new venue and contribute to the funding of the building with 0 stake in ownership of that building.