The photos and videos will still be available on the original device where they were stored, and will only be deleted from the cloud. When My Photo Stream eventually stops working, users don't need to worry about losing access to their photos.
This could also be the reason why users aren't seeing recent photos from My Photo Stream on another Apple device, such as a Mac. Once iCloud Photos is enabled, photos from other Apple devices will no longer appear via My Photo Stream on iPhone. Another reason why My Photo Stream may not be visible is if users have already enabled iCloud Photos on their iPhone. Additionally, if the feature hasn't been used in a while, it might no longer show up as an option. If users have recently created their Apple ID, My Photo Stream might not show up as an option in Settings or in the Photos app on an iPhone.