The studios take more than 75% of the ticket price for themselves. The popcorn is keeping the theatre owner afloat.

Studios take a sliding scale percentage. On some new releases, 100% of the ticket price for the first week is taken, sliding to 25% after six weeks. For a theater to make money from the actual movie, they need films like Titanic or Avatar that had extended runs, otherwise, most of the income is purely from concessions. Coke and Pepsi sell their product extremely cheaply to many theaters (and shopping malls if they can work exclusives) for the branding rather than the profit.

And yet all those films make a loss !

Holywood needs some better (or worse) accoutnants

Yes. And without the popcorn, that money to keep the theatre owner afloat would have to come from somewhere else, e.g. the ticket price.

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.