It's a legal issue. The law (in my opinion) took a wrong turn a few decades back, when software was a new thing. Instead of having to conform to the established "first sale" doctrine, which basically held that once you bought something it was yours and you could do what you wanted with it, software sellers were able to convince the courts that their products were entitled to special protections, and that they weren't actually sold, but just licensed on terms that could be as restrictive as the companies cared to make them. This has led to situations where you buy a machine, but it's totally useless because the you still don't own the software that makes it work, unless you negotiate a separate licensing agreement with the company that makes it, for which they can ask whatever they want.