[TA43]

They provide it but often not in the same product capacity, a common structure would be Sophos & CarbonBlack - two separate products by different companies. Additionally they'd need a third product to cover the *nix estate.

Defender, in its current state, rolls all of the above into one at a relatively competitive price point. Additionally, it receives new detections built off all the telemetry they get as a result of Windows Defender existing on almost every Win10 OS on the planet.

This leveraging of data on such a scale is letting Microsoft quickly become the market leader for threat detection & response.