Blame marketing, branding and pressure for value-add. There's no reason for anyone to have a VPN client you can see. It's all IPSec, OpenVPN, or wireguard under the covers. It should be handed off to the OS, but every corp needs to be a special little snowflake and show you their logo. (Yeah, I'm bitter, I fought with way too many crappy GUI wrappers for openvpn CLI) Once the app exists, there seems to be little pressure to make it actually good - one of them updated and literally removed the necessary client but just from the MacOS releases.
(ZeroTier gets a pass though because it's an uncommon protocol and I can't remember the last time I've actually seen the app open - as it should be.)
(ZeroTier gets a pass though because it's an uncommon protocol and I can't remember the last time I've actually seen the app open - as it should be.)