Streams are not under our responsibility. We do not guarantee or sell streams since it's illegal and you can get banned/blocked from Spotify for that.
When a curator adds a song to their playlist, this does not mean you will get a big number of streams immediately as many factors might impact it, such as the length of the song and its position on the playlist it was added to, listeners' behavior, etc.
Quite often people go to the playlist to listen to the same songs. Few times will they activate the shuffle mode, however, it might be less likely that they discover new songs added to that list.
Even after your campaign has ended, the curator can still keep your song for a longer time on their playlists and you might get more streams later on.