There aren't any official benchmarks yet, so no one knows how well the chip performs (except the handful of people on the inside). The "more cores = better performance" is absolutely true when sticking to a single manufacturer across similar generations, but you can't make simple comparisons like that when dealing with different types of chips. Since, if "more cores = better performance" was always true, then the AMD FX-8350 with 8 cores at $150 would rival Intel's 6900K with 8 cores at $1,000. However, there's a very large difference in terms of performance between those chips, and, in this case, the price tag reflects that.

I'd love for AMD to finally offer some competition to Intel and I'm hoping that Ryzen does just that, but until benchmarks are out, we don't know the answer to your question.