As long as the business model is real and credible, and as long as the people behind any idea are real and credible, then the market decides. In theory, and on a white paper, most of these ideas look great. There is no shortage of ideas, but if you wonder why some ideas take a long time to get executed and others deliver faster, then you need to think whether something isn't right somewhere.
I get worried when the price of a particular promise gets way ahead of its delivery reality.
That said, I do believe in special purpose blockchains that serve a particular segment, like the one Steemit is built on.