I actually have a Chromecast device
You're right, Chromecast's a really nice way to get streaming content onto the HDTV. I've fallen out of using it through plain laziness on my part, watching now either on an Android device or my laptop. I know a lot of people hate that, but I really don't mind a smaller screen if it's HD.
My wife and I have bought a fair amount of content over the years mainly from both Google and Amazon. I've not experienced it (yet) but I've heard that if a service loses the right to distribute something you've purchased--too bad, so sad. It just disappears from your library.