I don’t completely agree with Rossman here. You are buying the streaming right and not the file. What I agree on though is that they don’t make that clear to their customers.
They use terminology such as "purchase" to intentionally lead you to believe that it is a purchase and not renting. Also when they do make it more obvious that it is a license they make you think it is a perpetual license rather than temporary.
This is similar to buying a DVD. You don't buy the right to the video playing on your TV; only the right to play it on your TV from this exact physical disc. If the disc breaks, you have to buy it again.
It is possible for your disk and backups to break, or to be stolen, etc. But it’s just an unfortunate thing that can happen to anything you own. It’s different from the corporation taking away the rights of millions of people just because a licence ran out.