Err, that's not true. In fact, the only reason they can charge for that OS is because they can keep it secure going forwards. It's not that Windows is being dropped, its more like MS realized that there is a lot more potential to grow in other areas, without being tied up to Windows.

They have failed to keep it secure for as long as I can remember. They are still able to sell it despite that, because people own Windows-only applications.

I would have agreed if you were talking about Windows XP but Microsoft has improved their security standing a lot since then. I think its a little disingenuous to call them unsecure more than other systems in the industry. Also the security environment has changed dramatically where monitoring and alerting are becoming key components. I know for a fact that Microsoft is investing heavily in those areas.