I don’t know a lot about lemmy.world, but it seems to be running on “a server”. The person that wrote this may have used it as a simpler way to mean “the overall infrastructure that runs lemmy”.
However, if it really is “a server”, there will eventually be a breaking point where continuing to scale gets a lot harder, more complex, and more expensive. A lot of people don’t really understand that a site like Reddit has a massive infrastructure as its foundation. That’s how it can handle millions of connections, billions of comments, and stay - more or less - available.
It’s expensive to run.
Lemmy can’t ever hope to replace Reddit without some kind of significant investment in infrastructure and possibly development. If the code isn’t written to support scaling out (as opposed to scaling up and just throwing more RAM, CPU, and storage at a single system), it can’t replace Reddit.
That’s not to say that I’m not loving Lemmy. I do. I have barely opened Reddit since Friday after apollo died. At some point, though, money will become a factor here as well.
Lack of technical expertise does not equate to a lack of intelligence.