Let me start by reiterating that my post was written to give some kind of indication that the subjective experience may differ between individuals.
Yes and no: I didn't have the gall to demand that my employer purchase a non-standard laptop with a 4k screen because my regular computer needed a service. What's objectively true about this statement is that the regular Windows set of menu and status bars tend to take up more screen real estate than the Mac's system-wide menu bar; especially with the option to run applications in fullscreen and/or split fullscreen mode, where everything basically gets out of your way.
Earlier in my life, when I was forced to run Windows, I tweaked it until it behaved somewhat sanely in this regard, sometimes using third-party tools, etc, but that wasn't an option here, so I got the full disturbing picture of the Windows out-of-the-box experience on "low-res" wide screens.
I would bet that 99.99% of Windows users do experience needlessly sluggish software on a regular basis. Since I do maintain Windows-based software for a living and work with colleagues who are deeply entrenched in the Windows world of their own will, I know not much has changed there since I personally made the switch to an arguably more comfortable desktop environment.

The real estate issue, though, is more related to a combination of system resolution and design paradigms, as stated in the previous paragraph.
My point is that I shouldn't have to, and there obviously are a bunch of operating systems out there where you don't have to start out by cleaning out crap - especially in a system that's intended for business use and where you've paid additional money for business functionality.
What happened was related to the system repeatedly crashing horribly after leaving it to rest for a while. It probably says more of the interaction of Lenovo hardware drivers with the Windows operating system than about the Windows base system per se (and it speaks very favourably about the two Macs I've owned since 2010). But it also says that a Windows business laptop aimed squarely at professional users in 2018 has the same kind of issues I considered normal (for Windows) in 1998. There's a reason for why every Windows user no matter their competence level knows that you force shutdown your laptop by holding the power button for a few seconds...