They compared against HEVC as well. To quote the article: "This means that we can substantially raise quality, while saving bits, all with a very usable CPU footprint. We have found that the real-world compression/speed trade-offs for AV1 are in fact excellent, and better than HEVC."
And the business problem with HEVC is: "HEVC (aka H.265) comes with unacceptable patent cost, risk and uncertainty."