I think the main idea behind it is that as of yet we do not have an efficient enough method of launching things into outer space. ?Trust me, you guys are not the first people to have thought of that. ?I mean, scientists have the know-how to build a fusion reactor in theory, but it requires further technology (namely a magical conducting material) to get it working.
What I am saying is, IF and WHEN an efficient way to get the trash into space is created, this would be a good idea.