I would argue that what Steam did for video games is what Netflix did for movies and tv shows. They made the legal option way more convenient and affordable it wasn't worth the hassle to pirate. That has changed now (at least in Netflix's case).

I remember me being 14 and distributing stacks of 3,5" 1,44Mb floppies filled with copies of Doom to whoever wanted one, as long as i got the disks back later on

ahhh, the halcyon days of downloading Utada mp3s via dialup cuz no store outside of Japan, neither online nor brick mortar, even sold them.

and bragging about it on AIM!

I reckon Napster was the first instance of piracy entering pop culture and that was in the late 90s. Of course it existed long before that (think anti-piracy measures from PC games in the 80s), but I would point to that as the pivotal moment.

OP says ~2007 internet (asumming bandwidth and avail content) got good enough to become mainstem, not that I started around then.

Well yes, I was born December 27, 1998