That seems a very good way to phrase it.

The next issue then becomes cost. Which affects Lemmy as well: first there is the requisite effort to set up and self-host even a tiny instance (especially as it relates to potential spam and CSAM attacks), and second the network traffic costs. The latter may be tiny for a single user who only subscribes to a handful of communities, but someone trying to browse All and wanting everything to be available for their perusal (even if deleted soon-ish for storage reasons) will bear a much higher burden. Which depending on local costs may be trivially easy... or prohibitively expensive, but in either case the more data that someone wants to pull in the higher the cost.

And I imagine that Bluesky is either similar, or significantly worse.