There are other ways to do that besides pulling the data off the host machine. For example, they could prompt users to choose their OS prior to downloading and

There are other ways to do that besides pulling the data off the host machine. For example, they could prompt users to choose their OS prior to downloading and track downloads. Give different (or even identical) copies of the installer version numbers depending on the OS that was selected so updates only have to see what version you have installed to know which OS is in use. Maybe add a prompt letting users whose OS doesn't match the version they're running know that if they have issues to download the version for their OS... Seems over-complicated (and it is because they could just decide to stop supporting an old OS on their own using any number of criteria), but still probably less work than collecting and securely storing IP addresses and computer details, trying to anonymize that data, controlling access to that data, making sure it's all deleted appropriately, having lawyers review court orders for the data they've collected, etc.