Except it's not. Today, Windows wants you to use their media creation tool, which is more than just a "download bootable image and flash it to removable media" tool, but also actively slipstreams the latest OS patches to the install media. It ensures you get the latest OS on install with all the needed security patches.

Having a similar tool to automate not only bootable media creation, but also selection of distro and acquisition of install media would indeed make installation more simple. Unetbootin used to do that (still might? Haven't used it in ages), but IIRC, keeping the list of distros up to date was a challenge.