In the super bowl case, the elasticity of supply is zero. That doesn't occur too often in the real world.

That's because sports teams are deeply ingrained in our culture as well as our tax system (and exempted from monopoly restrictions), and there are substantial auxiliary profits to be had in allowing fans to see the occasional game.

Even though the supply elasticity is zero, that wouldn't itself invalidate the laws of supply and demand. The owners would have an incentive to maximize their profit by jacking the prices up until they have slightly less than 75000 tickets.

But they allow things like waiting lists and lotteries for tickets instead (and punish scalpers), because those represent commitments to keep watching the game (which costs them nothing), keep voting to build new stadiums on taxpayer dollars, keep buying Packers jerseys and hats, keep trying to get seats at the nearly empty certain-loss games in midseason with nothing on the line, and in general support the team until your death. If the stadium seats for the Superbowl were strictly a narrow for-profit operation, they would be auctioned in order to maximize profit, essentially.

From an economic point of view, demand perfectly balances supply... as long as price is free to fluctuate.

If price is fixed too low then demand can easily exceed supply.... at the too low price.

If price is fixed too high then demand can easily be lower than supply ... at the too high price.

Well "demand" doesn't just mean "want" or "desire".
Demand is the want or desire to possess a good or service with the necessary goods, services, or financial instruments necessary to make a legal transaction for those goods or services.