Exactly.

Lots of utilities which disable telemetry automatically are invasive as hell and sometimes break your Windows installation.

Check out https://github.com/Disassembler0/Win10-Initial-Setup-Script/...

Sure, but for professional use I'm not very interested in unsupported hacks that are liable to break things and/or be overridden and reverted by Microsoft in some future update. We deal with various kinds of sensitive and confidential information, and we have legal and contractual obligations to protect it, and so we need the ability to control where it goes on our terms. It's really as simple as that. If Microsoft won't give that to us, then we won't be Microsoft customers.

If it's for professional use, then you can use the official non-hacky method of disabling telemetry with the group policy editor available in Win10 Enterprise, server, and education versions.

Only if you have those editions, though, which typically no small business or independent professional does (nor home users, obviously).

Windows 10 Enterprise is, as far as I can see, essentially a different OS to Windows 10 Pro and the lower editions, presumably because Microsoft knows very well that its big corporate customers wouldn't stand for the kind of behaviour it's trying to inflict on everyone else but the big customers have enough money/lawyers/etc. to escape the trap.

The big change from earlier versions is that there used to be a mid-range Pro edition that was aimed at the smaller-scale professional market, with some of the more advanced features and without some of the restrictions, but also without the emphasis on having to centrally manage everything the way a large organisation usually wants to. In contrast, with 10, the Pro edition appears to be as broken as the Home one for professional use. I'm not really sure who the intended target audience of Windows 10 Pro is or why it exists at all.

If you are running Windows 10 home for professional use, you’re at best being negligent.

I run win 10 pro, just as I ran win7 pro before, for home use. A small business has no excuse to do otherwise.

You missed my point. Windows 7 Pro made sense in that market. Windows 10 Pro does not. You are literally relying on a system where you cannot maintain both proper control of your own resources and good support for things like security and compatibility updates.

You can do exactly that with Windows 10 Pro.

How do you turn off all phoning home and run a stable system with only security and essential compatibility updates applied if and when you choose in an officially supported way with Windows 10 Pro?