Lemmy is a very different conceptually than Voat. A major difference is it’s not just a single website, of course, it’s open source software that anyone can download and install, which makes it very resilient. The federation aspect is clever too, making it much more than if it was just a bunch of different, disconnected websites running a version of Lemmy.

Voat’s goal of being specific to a certain political ideology naturally limited it, too. It doesn’t seem that conservative ideology is particularly popular among whatever demographic reddit serves, based on the distribution of subs and comments. Maybe I’m wrong and conservatives just avoid reddit because they view it as a liberal/left site, idk.

Plus, as others have noted Voat was toxic from the start, being composed mainly of people from communities that were kicked off Reddit for breaking rules about hate speech and violence. That’s a very shaky foundation, obviously. Lemmy has recently gained tons of users of course, primarily people who ditched reddit because it sucks, not were ditched by reddit for sucking. Huge difference there too.