Would you prefer that the storage provider not warn you when you're close to capacity?
The entire reason for the warning and suggestion to purchase more storage to resolve the warning is demonstrated in your first post. It isn't unsolicited, as it is only generated in response to your behavior.
Most folks don't know what data is growing on their devices, and even if they did, would be hesitant to stop the growth or continuously delete data to keep from exceeding their quotas. I suspect that this is especially true with respect to photos. If you are relying on iCloud Backup for your device(s), the backup will fail if the allocated space on your iCloud account is inadequate.
With iCloud Backup, apps and your iTunes library don't count against your iCloud storage quota, but application data and photos do count unless you specifically exclude them from the backup.
JKG