Why, yes I do. Simply put, all the low hanging fruit x86 processor development has been picked already. The only remaining advancements are incredibly expensive to make, both in time and money, and as a result even Intel can't appreciably speed up x86 processors anymore.
Now that Intel is mostly standing still, AMD has a chance to catch up. It can benefit from all of the research work, process developments, etc, that have occurred, and implement its own version of the same advancements that Intel made over the past 7 years or so, much more cheaply than Intel did. AMD's limited budget may just be enough.
I actually don'tt think that Ryzen will be as fast as Intel's best. But I expect it to come within 25%, and for a reduced cost. My prediction is that x86 won't get much faster as AMD becomes more competitive with Intel, but it will become a lot cheaper. Intel's high end consumer chips that cost $350 now will be available for $100 in a couple of years, whereas without AMD's Ryzen providing the competition, they probably would only have come down by $50 or so.