Bitcoin was designed to be "electronic cash". Nothing should be changed in core that does not support this mission.
The title of the Bitcoin white paper - "Bitcoin: A Peer-to-Peer Electronic Cash System".
You should know that Bitcoin is an open source project which means it's open to everyone and of course development is a must and if the community agree to something for the better of the protocol, it will be reviewed as "Bitcoin improvement proposal" and and agreed date which modification will be added through soft work which means that even though you don't update your client to the latest protocol, you can still use the network efficiently.
bitcoin used to be secure.. where by anyone could propose something, but it only activates if majority update their node to be ready to fully validate the new ruleset.. this is called good security.. and is the point of full nodes
however now hardly anyone can make a BIP due to CORES control of the BIP list and their moderation policy of the tiered system of even discussing proposals before they can even be listed in cores BIP list
and then we have core that slip in nw features without needing community agreement because as you say and admit it does not require users to upgrade to agree to the new feature