Okay, first post, and I'm very upset that you're making me defend business owners.
Point by point:
The salary cap is not illegal. It was negotiated and agreed upon by the owners and the labor union. Not only is it not illegal, but I believe that you will find that most unions, particularly labor unions have very clearly defined salaries. You progress until you hit top rate (the salary cap). In an entertainment industry, such as sports, television, you are free to negotiate your own salary in the market. However, there is nothing that prohibits management and labor from negotiating salary floors or caps.
Limits on cost of products. There actually is a limit. It's called supply and demand. Teams charge what the market will bear for tickets and t-shirts. If you would pay $40 for a t-shirt, they will charge you $40 for a t-shirt, regardless of what their players are making.
And parity is the real purpose. And it has worked. Since the salary cap began in 04-05, only one team has repeated as Stanley Cup Champions. And while three teams have won the Cup in the last 7 years (and four in the last 9), the Cup runners-up have never repeated, and only in '07-08/'08-09 did a runner-up return to the Cup to win (Pittsburgh).
The draft is the only way to disperse talent throughout the league to promote parity. In leagues (and in times) prior to a draft, the richest teams in the biggest cities were able to control the majority of talent (eg: Montreal Canadiens, New York Yankees, Yomiuri Giants). It is in the best interest of the game that players be drafted into the league.
Now, development. The NHL drafts players at 18, many from the CHL, which is a system that they nurture through financial assistance as well as mentoring. These players who are drafted are either then reassigned back to the CHL, or sent to the ECHL or AHL, where they are...wait for it...developed. They are developed in the NHL system, which shares its young talent with leagues across North America. This is good for the game, because a hockey fan in central New York can see kids who will be playing for their favorite team (whether they're Sabres, Rangers, Islanders or Devils fans). Minor leagues often market themselves as a development system, "come see the future stars of the NHL", which helps them sell tickets, which keeps their barns at least partially full with fans. (I was at the Providence Bruins game, and fans were wearing Boston Bruins t-shirts than P-Bruins t-shirts).
You say Patrik Laine should have gotten $3million. He is, per year. He's in the 2nd year of a 3 year contract with a base salary just shy of a million dollars, with performance bonuses per year that push him to over three and a half per year on a $10million/3 yr contract.
If he is unhappy with those terms, he is free to negotiate with teams in the AHL, ECHL, FHL, KHL, or any European elite league. Mexico has a league now. Logos and sweaters look dope, too.
There are many good fights to fight, this is not one.