re: Aliens may have economic issues, too
There's no doubt economics as we understand it exists on other worlds. And there's also no doubt alien civilizations somewhere in the universe have collapsed due to economic constraints. This could account for a percentage of Fermi's Paradox. But the universe is bursting with resources (Perhaps food being the one exception). There would have to be civilizations out there that succeeded in tapping the limitless energy sources of space.
An interesting theory but it has holes in it.