Really? I have never worked for any company from a ****** little Indian perfumery to GlaxoSmithKline to the nhs ( the worlds bggest employer) that used any computers even close to the specs of a mac. They paid through the nose for them and spent a fortune in IT keeping them running. Any software can be loaded on a mac and the hardware will match anything but the most high end workstations (see iMac Pro). All reports of longevity and reliability can have ever seen showe Apple computers way out ahead of the competition it’s that simple.
I have no idea what you mean by business grade I haven’t used a work computer that was as good as my home machine in 10 years, so business grade to me just means rubbish!
You're confusing home use with fleet use - You can spec an HP Zbook with 128GB of RAM if you want, right now - That's fine, but if your employer doesn't refresh the fleet (depends on the contract) then that 128GB RAM laptop is going to be pretty dull in 10 years time.
Loads of companies hold onto old hardware for aaaaaages simply due to costs - Some companies still use XP. If they were using Macs, they'd still be using Macs way slower than the one you currently use.
You should see some of the Microsoft Extended Support contracts floating around the place, we're talking tens of millions spent just to keep old kit in support.
"Any software can be loaded" - No, just no. At home, sure - But try getting into Cognos builds and things like that. Just no.
Apple doesn't even provide support options for their hardware like the big players too, they don't need to, they've pulled out of the professional/business space with the death of the xServe etc. OpenDirectory integration is way behind.
You are very correct in the fact that only supporting one set of hardware is much easier/cheaper than supporting many, but that's exactly why all of the big players in this space do exactly that. Just because they provide 10,000 different (crap) options for the home user does not mean the business lines they provide are the same, with the amount of money some of these support options are worth it would be silly...
Even custom orders can't be done through Apple, things like laptops ordered with a 4K display but no webcam, no fingerprint scanner, no Bluetooth/GPS, no USB and no touchscreen are an every day thing around these parts, wereas Apple just don't provide this service anymore. You used to be able to in the G4 days. I know such a laptop would make 0 sense for home use, but when you're a bank working with sensitive material, such use cases start to creep in...
Does Apple even provide wired keyboards and mouses anymore? Imagine trying to keep 10,000 different wireless keyboards and mouses 1) in the building and 2) charged and ready to go. Even that would be a nightmare. Man.