To get a team you need two things, 1) ownership with an arena or the ability to build one, and 2) the willingness to spend what the NHL owners consider market value for a franchise.
It really helps if an NBA owner that already has a building also wants to own an NHL team. You can really justify adding a second major tenant to the building you already own, and to the building you are likely to build in the near/mid-term future. That's 82 nights a year covered. For years, the answer to why isn't the NHL in SLC was that the Jazz owner didn't want to own an NHL team. A city that size has no need for two arenas, and it's hard to make money playing in someone else's barn (assuming its owner will let you use it). Today, the Jazz owner does also want to own an NHL team, and the building they play in, and that makes a huge difference.
Houston has been plagued for years by an NBA owner that didn't want an NHL team or to share the building with a separate NHL team owned by someone else in Houston.
Houston now has an NBA owner who IS interested in having an NHL team. Yet he's currently unwilling to spend what others are willing to spend ($1B+) to acquire a relocated or expansion franchise, and that is the current holdup. Smith in SLC was willing to spend that coin (after Ottawa sold for that coin too). The Rockets owner may have to shift off of that hill, because there are other cities that do value NHL franchises accordingly.
...or what is most likely, the NHL remains patient and Houston expansion sits on the back burner, which is also fine. I don't expect them to go to Houston for less than market value, though. Devaluing franchises is the one thing that will drive the owners to fire a commissioner. (I mean, they can just veto the sale/expansion itself, so they won't actually allow him to devalue franchises, but the point remains).
In a lot of ways, you can distill the entire job of the commissioner of a sports league down to driving up franchise values for his constituency, which are the owners. That's who the commissioner works for, and that is what they prize most. If a Houston billionaire sports mogul wants a team but doesn't want to pay what the owners consider the going rate, then they won't give him a team until that changes.
The commissioner doesn't have a vote, incidentally. He has the power to set the agenda, and that is real power because you don't call any votes until you know you are going to win them. Yet he can't make them agree to green-light a team in Houston for peanuts because that is squarely against their interests. One day, they will probably want to sell their teams too.
