You know what combats this?
User education. You have to be incredibly ignorant (not in an insulting way) and unfamiliar with how computer Operating Systems and web browsers work to fall for such a transparent scam.
The scam starts by redirecting users to a fake Microsoft website which suggests there's a virus on their PC and prompts them to phone an emergency hotline.
These are not Fake Windows Updates. Like I said, they don't even involve Windows Update. They are arbitrary pop ups and redirects that occur when you visit shady websites. A better question to ask is why users who don't even have the experience and understanding of how the system works to be able to discern a real, legitimate message from Microsoft from a basic Window.Alert() are browsing the sort of websites that impose pop ups and redirects. It's the same problem that causes people to so easily fall victim to malware via torrents; They basically know just enough to get themselves in trouble. It's like knowing how to put a manual transmission car (to callback a previous thread!) into gear but not knowing how to use the brake.
There is a very good reason that Browsers have moved their Alert dialogs from standard OS Dialog boxes to boxes contained within the website, and prefixed them with text indicating that the message is coming from the website- it's an attempt to help more informed users who understand the difference.
And it's hardly limited to tech, either. For every "Microsoft Support" scam that preys on people's ignorance of Windows and computers, there is an IRS Scam that preys on people's ignorance of how the organization works. For example, I know somebody who fell for the IRS scam but was stopped when buying gift cards. It's a somewhat understandable kind of ignorance to not understand the IRS. It's quite another to think they have jurisdiction in Canada. It is this sort of almost wilful ignorance that scams prey on.
