I thought the real issue here was biodegradability. Since most disposable cups are not recycled, the ease with which they could be recycled matters a lot less than the fact that styrofoam is forever. Then again, in the absence of oxygen and light, I'm not sure that paper cups will ever degrade much in a modern landfill....
I've never really understood why people get worked up over landfills. Digging a giant hole and filling it with trash is a perfectly rational solution. It isn't as if we're importing mass from space and converting it to trash...we're digging up stuff from the ground, using it for awhile, and then putting it back in a slightly different form. If we ever find a use for the styrofoam in landfills, we can mine it back out again.
I don't get worked up over landfills, but I do get worked up over all those bits of styrofoam that never make it into the landfills and hang out on the beach or in a park or wherever they happened to land - I'd greatly prefer those bits be replaced by something biodegradable.
According to this website (http://www.worldcentric.org/about-us/faq#pla6) it takes at least 180 days for a corn-based cup to biodegrade in a compost. Biodegradable or not, it's probably more efficient to hire people to just clean up the trash periodically instead of hoping for a biodegradable solution.
Modern landfills can actually be used as an energy source to some extent:
"More recently, it has been recognized that this landfill gas represents a usable energy source. The methane can be extracted from the gas and used as fuel. In the North Wake County Landfill, a company collects the landfill gas, extracts the methane, and sells it to a nearby chemical company to power its boilers."
I've never really understood why people get worked up over landfills. Digging a giant hole and filling it with trash is a perfectly rational solution. It isn't as if we're importing mass from space and converting it to trash...we're digging up stuff from the ground, using it for awhile, and then putting it back in a slightly different form. If we ever find a use for the styrofoam in landfills, we can mine it back out again.