One would think it was practically designed to be that way........................
It’s the Kodak formula.
Gets windows for free and pay for the anti malware and virul protection.
Windows began life as an outgrowth of MSDOS, an application running on MSDOS, then NT was born, and slowly with XP and Vista it tried to bolt on some semblance of security.
Windows has improved tremendously since then. Win7 was outstanding in many respects, and Win10 was an security improvement over that, although it also introduced some unloved quasi-spyware features.
But it's still the case that "back-compatibility" with the older releases has been one sticking point throughout. Microsoft's people just can't wrap their head around the concept of "Security-By-Design" and instead they settle for "Security-By-Incremental-Bolt-On-Patches".
It's unfortunate. But it's unavoidable, given the Microsoft mentality, and the perceived necessity of remaining compatible with ancient releases.