yes, but...

$10 ticket + $10 concessions = $10 net revenue (%25 of the ticket and %75 on concessions)

$20 ticket + no concessions = $5 net revenue.

It is the same reason CEO's take $1 salaries and stock grants/options. Salaries are taxed at %36-9 but long-term capital gains tax is only %15.

Yes. Though we wouldn't know whether the percentage rates would stay the same, if concessions weren't allowed. The current rates were negotiated with concessions in mind.