Not sure if it was called "beta" or "alpha" and "closed" is of course up to interpretation, but it was indeed by invitation. Swedish law at the time (still?) had a clause about permitting sharing copyrighted material within a limited circle, which I know Spotify engineers referred to as somewhat legitimising it. I also know for a fact that once the invite-only stage ended there was a major purge of content and I lost about half of my playlist content, which was the end of me having music "in the cloud". Still, this is nearly twenty years ago, so my memory could be foggy.

When I first started using Spotify, a lot of the tracks in my playlists had titles like "Pearl Jam - Even Flow_128_mp3_encoded_by_SHiLlaZZ".

Always made me chuckle, it looked like they had copied half of their catalogue from the pirate bay. It took them a few years to clean that up.

Yes, when the entertainment industry came onboard they immediately made the service much worse. I reacted the same way you did.

IIRC, 2008, a little less than twenty years.