For an online service to get popular, it has to be either a new, really interesting thing with a lot of advertisement, have the support of some big celebrities (usually through advertisement too), or literally pay people to come en masse to artificially make it popular, so that more people comes organically (so, basically, a large advertisement budget). It also have to be easy because most people can’t read more than a few lines of explanations on why things are different.

No lemmy instance have none of the pre-requisites, and the accessibility is not really there for the general public, due to various things. My main gripe is that federation and local moderation means you’ll have to create multiple account to access content from certain groups of servers, which is a lot to ask to people that can’t be asked to make even one account, but there are other minor things too. The sheer choice of instances and client, seen as an advantage by some, is simply a bothersome annoyance to people used to large platforms doing all the work of deciding what’s good and bad for them.