Because it’s an asinine practice from which windows is moving away through winget, and which made the open source community to write a package manager for mac from scratch – homebrew.
And if you think about it for a second, you will realize that it doesn’t exist on Android and iOS at all. E.g. 99% of users only install from a centralized repository called “appstore” and nobody is ever downloading an executable installer.
Basically, you’re uninformed, and blatantly defending your uneducated way of installing software.