I don't see why you think you can treat "piracy" as a single independent factor. File sharing is an intimate feature of what the internet is today, and without the internet many bands (especially non-mainstream ones) would loose their main base for advertising. What I'm curious about is why it took the industry until 2003 to be innovative and use the internet to their advantage through digital music sales. Seems like they just became stuck in their ways and failed to realize that CDs would eventually fade away just like cassettes, vinyl, etc.
Do you remember trying to download a file in the 90's and early 2000's? You couldn't download a whole lot of music, especially not if you wanted quality, becuase the technology simply wasn't there. I remember getting DSL and being excited that megabyte downloads would no longer take like fucking 20 minutes.
Simply put, it wasn't a big enough issue with slow as fuck internet, and it wasn't as viable to create a company to sell media with a slow as fuck internet.
Even if it was a bubble, there can still be other factors. Why pick 1982 as your "realistic" level?