I've have had two tours of this with two different companies. The 90's Macs were a disaster and I wouldn't have recommended that any company standardize on any of them.
I was a PC and Mac support guy in that era. OS8-9-X. People would brag that their Macs never crashed, but when I came to repair their computers, it turned out that "Well, it only crashes a couple of times a day" or "I have to restart it a couple of times a day." Well, that isn't not crashing.
Also, they were using a terrible Mac support guy who WAY overcharged us. Calls went down 75% when I took over support, but the Macs were never trouble-free.
Here's my Why Windows is Better (or At Least Better Engineered) argument:
Apple controls all the hardware, OS software, firmware and (critically) drivers. There is very little outside the Apple ecosystem. Macs should never crash and never need need updates. But they do and they do.
Microsoft has NO control over what hardware Windows will run on or how the drivers are written (and drivers used to be 90% of problems). Everything is outside the Microsoft ecosystem. It's a miracle Windows boots at all, let alone runs so well.
Also, the obsolescence of Macs: I have a Macbook that became a paperweight after 10 years because Apple decided I couldn't update to the latest OS, and software I needed didn't support the old OS.*
My desktop PC is about the same age. I can install the latest version of Windows 10 on it without problems. (As it happens I still use Win7 and it's rock-solid.) Windows may cut support but they don't arbitrarily decide my PC is too old and I need to buy a new one. The motherboard/chip/RAM combo has outlived two primary HDDs.
For a while I ran Windows (desktop). Mac (couch laptop). BunsenLabs Linux (travel laptop). Mac was the most troublesome/crash-prone, Windows a VERY distant second, then Linux. I've since simplified my life, Windows on everything and one PC that dual-boots Linux.
Run good antivirus software, don't open questionable attachments, don't surf porn (or at least be smart if you do it), shut down properly, and keep the HDD defragmented, and your PC will run like a top for years.
To be fair, though, I do see a lot of PCs that haven't been kept up properly (ie my rules above) and run like crap. That doesn't seem to happen as often with Macs -- of course Mac people are convinced they need a new computer every 2-3 years, so maybe if they wait long enough...
But our current ones for the past 10 years have out paced our PCs for reliability without question.
Yes, Macs did get much better when they abandoned their crappy home-grown operating system and switched to Unix. All they needed was a 30-year-old operating system to fix many of their problems.
As long as Apple fans don't get wind of the fact that they can get the same virus-software-free experience for 1/3 the price with Linux, Apple will be fine. Good thing the phones and watches are selling well.
* This was a MacBook 2008. I decided "Screw Apple, they can't tell me what to do" and installed Linux. It ran great (MUCH more reliable than with OSX) until the touchpad died. One of these days I'll replace it.