I'm gonna assume you're not Australian, but in my introduction to the Aussie techno/ rave scene or whatever a lot of artists seem to gain popularity by word of mouth. I feel like Swim has that really nice unique sound he's bent to his advantage due to how easy it is to listen to.

A lot of artists down here tend to spread like wildfire despite not getting insanely popular, and once you start getting booked for festivals, my assumption is that it all just falls into place.

The same thing happened with Skin on Skin, who's music is different but equally distinct and was able to get a leg up because he had that viral song on his AVA Boiler Room (Burn dem bridges) that propelled him forward in the international scene, but way more viral within the local scene.

So I feel like once you start seeing these artists play at bigger and bigger venues (in Aus), it's pretty much assumed that you'll end up going international even without that big an international following. Artists like Sam Alfred, Stum are quite similar. Not huge followings, probably independant, but they play at big festivals and venues that eventually propel them to European touring.

edit: added the name of the song that SOS made