I suppose it is true that you can only learn so much from anal probings. One asshole is pretty much the same as another.

All of them? The Fermi Paradox is a problem because any answer has to apply universally or nearly universally, to all possible societies.

So this scientist suggests that all possible alien civilizations got bored and turned inwards? None of them bothered to make great works, or berserkers, or whatever? That's a rather extreme conclusion and, I think, wholly unjustified...

It's still a great mystery. To me it suggests "new physics" -- namely that any alien society sophisticated enough to build, e.g., Dyson Spheres has discovered a better way to harness energy in space and time, perhaps via methods which are difficult or impossible to observe.

A solipsistic alternative, but one that makes sense and gets around the universal objection, is in the "Zoo" and "Planetarium" hypotheses.