The speed improvements based on OS are:

1) Reduced telemetry and background services. 2) More efficient resource management.

Windows is super bloated when it comes to number of background task that transfer information to Microsoft and how much of the system resources their own applications need. Weather APP for example.

Windows telemetry can easily consume one CPU core after startup for 5 to 15 minutes depending on the age of the computer.

Windows updating system uses even more system resources than a Linux distro updating system. Linux is simple file copying-replace while Windows has to perform logical transactions because of how bad the bones of the OS are.

It can take _cleanmgr_ 15 minutes or more to clean up a system when selecting to remove old Windows update installers. Linux just has to mark the file as re-usable and move on. _cleanmgr_ does not even clean out all of the Temp files and requires manual interaction to do so.

Worst of all, Windows makes it a complete pain the ass to manage air gap system with updates. Linux just needs to create a HTTP server pointing to the packages on USB drive.

I think we spend a little bit too much time optimising startup time.

Anything more than 3 seconds and less than 45 seconds is perceptibly the same, it's the same level of inconvenience unless you're in a rush.

.. but I can't honestly tell you the last time I booted my Macbook from cold.

Worthwhile suspend/resume is a much better goal for the modern computer user... Windows fucked us all with s2idle, including themselves.