There is a Sync button in the Android client; Apple clients have never had a sync button that I recall.
Historically, the process was: channel properties were brought into the client upon first launch; subsequently, all future changes to a channel's status was localized to where the change was made and did not affect other devices. (Meaning, future status changes on the server did not affect the client, and a client's changes did not affect the server nor other clients.)
I understand your request, and you are welcome to it. However, how you claim things always worked or used to work regarding syncing channels is not accurate. The current supported method is through Channel Collections. You don't like that option and want to do it differently; you are welcome to ask, but I doubt the situation will change. (I would not be fully surprised if the sync option was actually removed from the Android client in the future to keep consistency across platforms.)