> Printer firmware does not get updates.

Sounds like you've never owned a printer before...

> IF that ever happens, which is super duper unlikely, then kill it since the clients are unfixable.

So have a possible security hole with no active developers until a third party finds a vulnerability, then shut it down?

> But this is not an ongoing cost.

You would still require SRE support for keeping this thing up running. You would also open yourself up to a lot of risk, losing user trust and potential lawsuits if it ever was hacked.

Everything you wrote sounds like an elaborate troll but I'm assuming that you've just never worked on a large system before.