Linux is one hobby - a hobby that squabbles and fractures like a sack full of damp cats, admittedly, but all broadly united under the heading of "linux enthusiasts". There's no active communities for, say, sewing or 3d modeling or baking or hobby programming or game development or ttrpgs or woodcarving or calligraphy or cars or etc. etc.
Hell, we barely have communities for porn. I'm keeping the bdsmgonewild community supplied with OC almost on my own ( <3 you Avelo for everything you do!), and although engagement is great, it's still painfully slow to build communities.
I have great hopes for the lemmy/piefed/fediverse, it really does seem like we're past the point of criticality and we'll get there eventually, but it's simply not there yet and that's what we really need to establish ourselves.
Right now our only culture seems to be linux, halfhearted memes and political infighting.... and furry shit, I'm told, although I'm woefully lacking in furry content :(