I've read your article yesterday and this passage kept me up at night. It might just be that you unintentionally found a solution to the Fermi paradox. I struggle to put it into words, but interstellar travel might be almost like trying to pay your way up the Ponzi scheme. It wouldn't work, because the amount of money you'd need to climb to the upper layers keeps increasing faster than the revenue you suck from the layers below, so you're always in debt (which keeps increasing). The same with materials and energy that you might need to mine the asteroids or build a Dyson sphere. It would be an interesting calculation, but my gut tells me it wouldn't be possible and it is all just wishful thinking.

So far my best guess for the Fermi paradox was along the lines that Kim Stanley Robinson explores in Aurora; that is that we are an integral part of the biosphere and can't survive without it. By analogy no aliens could do it either (without their home planet).

Otherwise very good article, thank you. :)