It's definitely not all the new controllers, although with the UDM line you might be right. I think there's a huge intersection between people who would buy those specific devices and people who are perfectly happy to have remote access to their control plane in the cloud.
It is also about dark patterns. I never had the cloud option enabled. One night after a long day I upgraded the controller software. I noticed a message like “do you want to login?” and wasn’t awake enough to realise that it asked for my ui.com account and that after that cloud management was enabled and my phone switched to authenticate from a direct connection with the local credentials to using the ui.com credentials.
It looks like what I was referring to is that they recently made the initial controller setup on the cloudkey require a cloud account [1], but you can migrate to local only after the initial setup.
So the only remaining 'local only' from start to finish is for self-hosted I guess.
I have a cloud key gen2 plus and do not have a UI.com account. I would classify getting the network controller setup without having one initially "mildly annoying but worth it".
I'm also floored at the number of people who are spinning the existence of a self-hosted controller as somehow a bad thing...?
The UDM and UDM-Pro force you to set up a UI.com account, and cannot be used with external Unifi controllers like one you might run on a server, PC or cloud key (Ubiquiti's management software on a Power over Ethernet powered dongle, does not require a UI.com account).
They do - first thing I did though was then go in and add a local account, and disable remote access (I have a wireguard tunnel that terminates on a server behind my firewall if I need remote access).