Tildes simply doesn't have the goals of "reddit alternatives" that are hoping to launch a new, popular site. It's just doing its own thing. Personally I find it refreshing, but it's definitely not for people who want to be part of the next "reddit" with millions of other people.
Sure, I definitely respect that and it is one of the things I like about it. I like the way it's focused on conversations over cut n paste memes.
But I think I've found a similar experience here on Kbin by blocking meme heavy groups and joining more specific communities. I'm still going to check out Tildes every now and then though