That might very well happen, but for my own usage, no thanks. I'd rather have a streaming box with a nice interface rather than mess around with a little 5 inch screen to get things playing on the TV. When I'm at home, I don't carry my cell phone around with me and in fact, rarely even use it inside the house. I might have a tablet with me, but that brings up the second issue with what I see above -- why would I want to stream data from my tablet directly to the TV? That can eat up battery life and I wouldn't want to have to make sure I have my tablet with me to watch TV. I thought (and please correct me if I am wrong) that Chromecast generally didn't stream data from a tablet or phone; you found the content with the tablet or phone and "chromecasted" it, meaning the Chromecast would get the address and pull it from the internet or a local network device. Is that not correct?
What I'd like to see is for everything to move to Wi-Fi for remote control purposes and then maybe tablets would become the remote control for everything in the house. Yes, you can do that now but it generally requires third-party IP to IR converters.
I confess -- I just don't "get" Chromecast as a media streamer. Sure, I bought one, but I bought one not for streaming purposes but for the potential that third party apps could unlock. I was mainly hoping for a good way to wireless display my PC's desktop on a TV and so far (again, correct me if I am wrong), I don't believe that is yet possible outside of casting tabs from the Chrome browser.
For me personally, my Rokus are far superior. I can see the possible advantage of leveraging a Chromecast with Plex and using Plex's superior tablet interface to select movies to stream from the backend server, but again, the Roku Plex interface is "good enough" and is easy to navigate with my Harmony remote.