The problem is, even for large companies, Kerberos can be quite the pain. It's fine for fixed position desktop computers physically located on site or at a remote site with a hardware VPN tunnel - that was what it was built for.
But that is rarely the case any more. People use their own devices (BYOD) that aren't integrated into AD at all, they're using them outside of the office which means there is no VPN available at boot time to deal with token issuance, and the modern "zero trust" crap that uses weird packet filtering black magic instead of proper tun/tap virtual ethernet devices often doesn't play too nice with archaic authentication tools.
On top of that, implementing support for Kerberos in a Dockerized world is just asking for pain.
But that is rarely the case any more. People use their own devices (BYOD) that aren't integrated into AD at all, they're using them outside of the office which means there is no VPN available at boot time to deal with token issuance, and the modern "zero trust" crap that uses weird packet filtering black magic instead of proper tun/tap virtual ethernet devices often doesn't play too nice with archaic authentication tools.
On top of that, implementing support for Kerberos in a Dockerized world is just asking for pain.