Of COURSE there's "collusion" going on. The owner's "collude" most of the time to protect the strength of their product (and profits). The players and agents "collude" to drive up contract prices. Sometimes owners and agents "collude" to negotiate unofficial deals while the player is still with a different club. Sometimes coaches (technically on the "team" side of things) and players "collude" to form bounty programs to remove other players from the equation. They ALL "collude" when it comes to driving up costs to the consumers... which results in more money for ALL of them. They can do this because the game itself is stunningly popular.
Like it or not, "collusion" among the owners has actually led to the structure of the game today, and is a HUGE factor in why it captivates the largest audience in the country. It's created a league where virtually every market thinks their team "has a chance" when the season kicks off. When labor strife broke down that structure for a brief window... a time which the league had basically warned the ownership collective about well ahead of time, and cautioned them that certain actions DURING the "uncapped" period could result in penalties AFTER it expired... 28 of the 32 franchises stuck together. Yep, that's "collusion". 4 did not. 2 of those 4 basically jaywalked when they thought nobody was looking, and they got slapped on the wrist. The other 2 hopped in a convertible, put the top down, and blew through the red light. And a camera caught them waving their middle fingers as they went through. Okay, maybe I'm exaggerating a bit. But that's how the league treated it. And it's collusion that they all signed off on at some point as well.
The "two owners" that everybody seems to dislike (one of which is even heavily disliked in his OWN market) both look at their own situations... their stadium deals and fanbase and gobs and gobs of additional cash they feel they deserve... and see an opportunity to make HUGE profits for themselves while also getting a substantial leg up on the rest of the league. But the league has operated for decades now in a way that tries to prevent that.