In Seattle at least they do posters. Mostly in Cap Hill (the gay area). The super small stuff is generally social only but anything with an actual venue will pop up. 19hz is also a good resource, it's searchable and city specific.
19hz has a good listing of events. A lot of it is announced on Instagram or Telegram (or the old classic of looking at the fliers on the telephone poles of cap hill). Renegades still happen (the bridge has been a super popular spot) but that season is sorta over. I more favor the Kremwork (that's more my scene) or digital hardcore shows which seem to just pop up everywhere.
As is mentioned elsewhere a lot of that might be the case of just no one talking about it publicly. I went to high school in the era when smartphones just started to be a thing. No one was really talking about sex out loud, people would get caught with drugs occasionally (a lot of xanax and weed), but why would anyone talk to the person who sat at the lunch table with the kid who wore a tail everyday.
I was also in one of the first schools that issued laptops to all students. The use of them was similar to how the parent post described smart phones. The honors/ap kids would either type notes or just not use them. The CP kids would be on... whatever the unblocked site of the day was (people figured out pretty early on that google docs/google wave were good ways to chat). The weirdos like me were playing cat and mouse with the tech people hosting proxies, imageboards, and meebo (IM client) repeaters. I'll never forget the day we went to the stupid url we used for it, and it redirected to barney.com. We also had a rather robust sneakernet set up for distributing giant packs of flash games and early versions of minecraft.