Still significantly larger compared to most Linux container images, and even more so than something like Alpine.

This different is pointlessly fetishized. Once layers are cached on a node they are cached on the node and it makes little functional difference to startup times.

There's also the small matter of: nobody will help you with Alpine bugs or CVEs. You are on your own. For something like Windows, you can pay Microsoft for any level of care you feel makes business sense. Same for Ubuntu or Red Hat.

Is Alpine 8MB containerized?

Yes and roughly 3MB compressed.

Yes, agreed, it's amazing how many more feature Windows ships than Linux, and that's only the "nano" version!

Like what? I find that especially when comparing Nano Server and Linux, that Linux is much easier to manage and has nearly unlimited features that can be used or installed via a lightweight package manager when building your images.