Obligation? Far from it. I've worked at some poorly staffed companies. Nobody is maintaining old VMs or container images. If it works, nobody touches it.

I worked at a supposedly properly staffed company that had raised 100's of millions in investment, and it was the same thing. VMs running 5 year old distros that hadn't been updated in years. 600 day uptimes, no kernel patches, ancient versions of Postgres, Python 2.7 code everywhere, etc. This wasn't 10 years ago. This was 2 years ago!