Crowded? No. Littered? Perhaps, depending on the altitude. The article you linked says the bulk of the existing debris is from a few isolated incidents.

These satellites are generally low enough tha their orbits decay after a couple years if they don't boost themselves, and then they burn up in the atmosphere.

Space junk is actually much _less_ of a concern in LEO because it's low enough that stuff de-orbits on it's own relatively quickly, so you don't get the long term accumulation that you can get in higher orbits

In terms of satellites, yes, very.

In terms of independent operators, not so much. If Starlink goes down or ceases operations in a given region or to a given customer, there are few alternatives right now.

u/lxgr was referring to the business being crowded/not-crowded, not LEO itself.