the new Ghost Rider comic is $3.99, same as the latest Guardians of the Galaxy comic by Brian Michael Bendis and Ed McGuinness (who are both decidedly higher profile than either creator for Ghost Rider).
If creative costs are figuring strongly into cover price of a comic, it's more due to rising page rates that are coming because of cost-of-living adjustments, not because comic creators are able to demand higher page rates.
Besides, I very much doubt that anybody working for DC or Marvel these days is doing anything purely out of the love of the characters. I start getting suspicious any time anybody suggests that love is a better reward than money 'cuz you can't pay your mortgage with a love of superheroes. I'm sure Jerry Siegel and Joe Shuster loved Superman, but I don't begrudge them their sense that they were grossly underpaid for what DC earned from the character.