I am willing to downgrade my statement “exceedingly rare” to “relatively rare”. It is certainly exceedingly rare in my sphere of experience. The last time I worked for a company that had shared computers was 16 years ago. This was on a trading floor set up for compliance. And they were in the process of phasing that out and making the computers on the trading floor just dumb terminals for Windows terminal server. So the desktops, themselves, ceased to be multi-user because they only ran the terminal server client, and it didn't matter which user that ran under.
After that, the only setup I've ever known was company-issued single-user laptops, and rarely BYOD. Company-issued single-user laptops are also what is used by all my friends and colleagues, where I have knowledge of such things.
With that said: The multi-user model is pretty broken on modern desktop Linux anyway, if you only look at how much stuff goes in $HOME these days, including software installed through flatpaks, configuration, even configuration with system-wide effects like power management and network, etc.
Many companies issue laptops. But even some of them have shared computers in meeting rooms or connected to equipment. Single user laptops are rare in medical facilities, banks, call centers, and many other places in my experience. Many shared desktops could be replaced by virtual desktop infrastructure theoretically. But this would cost more in many cases.
My network configuration is in /etc. Flatpak applications can be installed for system or user. And users able to install applications for themselves does not make the multi user model broken.
I have about five Fedora desktops running in my house that I share with my partners. Domain-style logins are handled by FreeIPA. Basic login with the KDE Fedora spin works great.
I've been meaning to set up auto-mounting network shares and such, but haven't gotten around to it; but the login management is very convenient and we use every day.
