Probably not. Most Linux admins know their systems and are able to navigate out of the situation with ease. But also most people don't use any corporate off-the-shelf software, because there are better options that are freely available.
Furthermore a Linux installation is dedicated and slim for one single purpose. The flexibility creates diversity.
No. They don't. They always need Microsoft support to solve situations and upgrades. You can also ask simple questions that they cannot answer. Try Active Directory: how to run AD in a secure fashion? Or: What services do rely on DCs in our company?
As a Windows engineer, the number of times I've seen other "engineers" open a case with Microsoft is insane. It seems to be a lot of their first reactions. No logs, no trying anything, just "this broke, why no work". I think it's that the Linux guys are mostly self taught, and the windows guys aren't.
I think the shower thought is centered around IF a ubiquitous bug that required physical access to the machine to resolve occurred simultaneously across all Linux machines.
If you couldn't remotely resolve the issues, regardless of your competence, simply the WALK to each machine and hooking up a KVM to each one would take a long time.
There won't be such case is my argument. No one patches a system "for fun" and automatically there except they really set it up like that. It would be only one kind of a case in one company.
Furthermore, you cannot compare Linux systems. A modem firmware with busybox is not the same as a Debian PC desktop. It works differently and has only the kernel in common. And in both cases they aren't patched at the same time. They are not even the same version, hell not even the same platform.
E.a. nothing will ever break like this. If it does, it will be one single case of a single IT department.