You can switch today by just cancelling one service and signing up for another. If, however, you are suggesting that somehow your internal "profile" of likes can be easily moved, then you should first learn a little bit about how these services work.
Each uses internal IP, unique to them, that won't work with a competitors technology even if they could get access to it. And of course that ignores all the issues of trade secrets and patents that your suggestion would bring up.
You can switch cell phone carriers because of a few very simple standards. But when you do you are not taking the majority of data about you. You are only taking your number.
I also challenge that all of this data is "your data." Let's take hacker news as an example. What is "your data"? Your username, passwords, comments, those all seem pretty clear. But what about your upvotes and reports? Is that your data? An upvote involves you, but also someone else's comment or story, so it's hard to argue that it's yours alone to do with as you please. Also, what about website log data? Is that your data? Logs about web requests that you make are definitely trigger by an action of yours, but the log message itself is produced by ycombinator software, so why should you get to "own" it?
