He's proposing $7 _total_ for the first 15 years. ($1 for the first five, $2 for the next five, and $4 for the final five years.)
If it's a flat fee for the first 15 or 30 years then it should take a lot of wind out of their sails.
If people start doing the math and saying "but at 60 years this is completely insane!" then just ask for a list of affected stakeholders that this would bankrupt. I suspect the only people on the list would be Disney.