And even if you DO post in small communities, half the time it's a toss-up as to whether anyone will see it.
I'm not sure about lemmy, but reddit was roughly 50% US users, so it was a good bet that if you timed posts for "early morning" US browsing or "after work" EU browsing, your post would do well.
Idk lemmy's demographic breakdown, but it seems more generalized (imagine that, a diverse fediverse!) around the world, so it's hard for me to tell when the most users will be active.
When I'm depressed, having someone sitting on the couch in my living room scrolling on their phone is infinitely more meaningful to me than someone who is miles away and texting me a lot or offering to help with things. It's probably part of my neurodivergence but having the person close in proximity while at least sort of paying attention to the room makes me feel less alone than having 10 people trying to check in on me all day.