I'm certainly sympathetic to the frustration of having to support every previous version of your software. If upgrades cost money, then people are incentivized to stay on old versions and then complain about bugs that have been fixed since then, and you can't tell them "just upgrade" because they don't want to pay to upgrade. Web companies almost never need to support old versions of the website, for example, and that makes them much easier to manage from an engineering and customer support standpoint.
