Time ... it will just take time ... the same thing happened at reddit, the communities didn't just blow up overnight and they didn't have competition either ... Lemmy is evolving in an early stage and it is handicapped by a competitor, so it will probably take longer to grow.

I don't mind it though ... we'll probably talk about it all in four or five years that right now are the good old days of Lemmy.

people giving up due to lack of niche/interesting communities

This is where people need to start making theire own communities. If you dont see it, make it. Its not easy, and you will likely have to be active in its growth, i think its worth it