Hm, Wikipedia seems a bit more pessimistic:

One implication is that the distribution of debris in orbit could render space exploration, and even the use of satellites, unfeasible for many generations.

Hmm, interesting. I have to confess I'm not at all an expert on the matter, but the general impression I get is that most serious discussions have looked at LEO becoming unusable for a few years. I'm surprised that one would think it could last for generations because the general maximum amount of time an object can stay in LEO before air resistance drags it down is generally on the order of decades at the maximum.

I wonder if there is some tradeoff where larger planets have a bigger gravity well that’s much more difficult to get out of, whereas smaller planets don’t have as much of an atmosphere, which means that space junk sticks around much longer, and also there is less surface area for it to cruise around in.

That is interesting, but I don't think it works as a strong filter. It would mean that every single species is being incredibly reckless with their use of low-earth-orbit, and even humans are already taking serious steps to minimize space debris production. The idea that planets slightly larger than Earth would have serious inconvenience for getting out of the gravity well, especially if they have a thick atmosphere is a plausible issue: the more likely problem with smaller planets is that they may end up then more like Mars.

Either way going to space is an expensive proposition with a dubious economic payoff, and society ends up retreating in to VR/drugs/etc. “Why hasn’t your society built self-replicating spacecraft?” could be a question similar to “Why do you keep playing video games instead of doing your homework?”

That might explain some species, but is very hard to see it as filtering out everyone. It means that no alien equivalent of Richard Branson, Elon Muks or Peter Thiel decides to break through that and go spread out, and that this happens for every intelligent species. Heck, spreading out at least somewhat makes sense purely for defensive purposes, in terms of things like asteroid shields which even if one is in a VR system one wants to take care of. To continue the analogy this would be akin to every class in every school having no student completing their homework.