Lumen Field and TMobile don't compete for the same events as Climate Pledge Arena. There is a reason why most cities that aren't NY or LA only have one major league arena.
The cost of arenas these days make it very difficult for a "second" arena to be profitable. AllState Arena outside Chicago was built in 1980 for $20 million. Thats a little over $70 million today. It can make it with minor league teams, second-tier college, and some shows. You can't do that at a $1 billion price tag.
There's a ton of faulty logic in that kind of thing. Pro sports teams have different "needs" based on what league they are in, and the price tag is totally dependent on those "needs." (Which are really "Wants of lucrative revenue streams from a long-season of games.")
But it's the LEAGUE AFFILIATION of those teams driving up the costs; and the simple fact is that no one talking the business of sports pays attention to, or cares, about the venues in a market that don't contain a top level pro sports teams.
For example, like every Convention Center in every city.
There's like SIX sport-sized venues in Las Vegas, but they serve an entirely different brand of entertainment, and it's impossible to say whether the venue is profitable or not because they're owned and operated on casino grounds, so like, of course they're profitable or else the casino wouldn't have built them.
The arenas themselves are GOING to be profitable, because they know how much it cost to operate the building for an event -- paying employees, turning on lights, etc -- and they're going to charge the person looking to use the facility a price that ensures they make money, OR they just sit dark that day.
The person who loses on money on events in an arena is the person moving to a bigger venue ONCE, not selling enough tickets to cover what they paid the arena, and then slinking back to a smaller venue the next time.