Not to mention at ~18,000 seats and enclosed, it should be able to host tons of other events. So you'll have 41 NBA games during the year but also dozens of attractions -- they're planning on ~200 events per year.
This helps, but it's still kind of a problem if you have an "event space" that nobody ever visits outside of events. Portland's Rose Quarter is like this, for instance - in theory it's an entertainment district, but literally all that happens there is (a) scheduled events and (b) people crossing between transit lines, so most of the time most of the area is just a big expanse of empty unused concrete.
It may take more than just the event space. The grandparent gives good examples and notes basketball and baseball are better attractors.
My town, Indianapolis, manages to integrate most events right into the downtown along with the convention center, hotels, and the financial district. Lucas Oil Field and Victory Field are around the corner on the edge of downtown; that section feels slightly more dead. But Banker's Life Fieldhouse is right there in walking distance and hosts concerts, circuses, Disney on Ice, etc., in addition to the main draw of NBA and WNBA games. So there are multiple events per week, plus conferences and conventions during the week. Plus youth sports events. When you add up the hustle and bustle of weekday office business, restaurants, and all the events, it feels like there's always something going on. Somehow all that fits in a relatively small downtown. There are no expansive parking lots like one might expect for a football stadium outside the city, so that helps the feel; I don't know where people park when Lucas Oil is full but somehow they get there.
