It's hard to say for sure. Sometimes it could be due to contractual negotiations between the music group and Spotify. Or maybe they just haven't made the decision to be available on that platform yet.
There could be a variety of reasons. Maybe Spotify didn't show interest in featuring them, or Boy Story's management has other plans for music distribution.
Maybe there were some licensing or distribution issues. It could be that the rights weren't sorted out properly.
Maybe it doesn't meet Spotify's content policies or there were some copyright issues.
Maybe it doesn't have the necessary licensing or rights to be available on Spotify. That's often the case for some music.
Maybe it's due to Spotify's terms of service or privacy policies that restrict sharing on stories.
Maybe it's due to changes in Spotify's policies or restrictions imposed by the platform in that year.
It could be that there were compatibility issues between the Spotify app and the story-sharing feature in 2019. Or perhaps there were copyright restrictions preventing the sharing at that time.
Maybe it was due to some technical glitches or changes in Spotify's sharing policies that year.
Maybe it's because your device and account settings allow it and there are no restrictions in place for this specific usage.
It's possible that there are restrictions or settings within your iPhone's privacy or app permissions that are preventing the Spotify sharing to story. Check those settings to make sure sharing is enabled.
It could be a technical glitch or a feature that's not enabled for sharing. Maybe there are some restrictions in the app's settings.
It might be due to copyright restrictions. Spotify has certain rules and agreements in place that prevent direct sharing of songs on stories to protect the rights of the artists and the platform.