How does HyperSpace prevent us from creating hundreds of accounts
That I don't know for now, but it's the exact question that I asked on the Steemit chat more than a year ago, when I realized every accounts gets some free STEEM (that was how it was going back then). A simple math calculation showed that if Steem would scale up, the Steem fund used to fund those accounts would run dry very fast. I was, of course, laughed at. One and a half years later, problem was badly solved with the new RC mechanism which led initially to a block halt of more than 24 hours. Thing is, people do not care about these things in the very early stages of the product. I know it would be good if they did, but they don't.
So, I really don't know how they're gonna solve this problem, but as a potential user I can hope they'll find a way. That's pretty much all I can do, as a user, right?