Antivirus software for Linux also has kernel access. You can’t intercept OS operations like opening files or launching executables without kernel access. And some of the companies I worked at also required antivirus software on Linux servers.
You can absolutely run Windows without an anti-virus, it has plenty of security features built-in.
It’s all a matter of trust. Do you trust your engineers to properly configure machines to be secure and not run exes from dubious sources, or do you trust a cybersecurity company to do it for you? Anti-virus software nowadays is more about restricting users from doing stupid shit.
Oh, and signed drivers aren’t about Microsoft validating and testing every driver. It’s about verifying that the driver comes from a trusted company and isn’t tampered with.