Not an easy question to answer.
I think the hunt for rarities adds to the appreciation of the tracks when you finally get them. I started tracking things like non-album tracks, extended versions, demos and remixes in the days before the internet. Back then, you had to do research via biographies, articles, published reviews, etc. Anything with a discography was my goal! I made copious notes on singles and albums, then hunted for those items in order to get the songs/versions.
Some early websites did monthly updates where they posted rare tracks, so when the internet arrived, I thought it was a dream come true. Then Napster, which offered even more.
It's different today, as the information is all much easier to access and the tracks much easier to locate. I could probably type in "Freddie Mercury Torrent" and download the entire boxed set. What does that do to the appreciation of the rarities, when you have hundreds at your fingertips which you've never heard?
I think it's easier for new fans to dismiss rare tracks now that they aren't so rare. With ten alternate versions to choose from, you pick the one you like and throw away the rest. If you only had one and thought the odds on hearing the others was slim to none, now that 'throw away' remix might get a better chance at winning your affections.