None of this is news (and it's not obvious at all if you sample over a shorter period), it's just steady progress over 4-5 years and includes major improvements to the common code from Intel, Red Hat and community developers. Once we are done catching up with our hardware development and proprietary driver work (probably another year) we should be able to spend relatively more time on features / performance and relatively less time chasing new hardware.
You can see from the benchmarks that a hardware maxes out around the same point irrespective of vendor (which kinda makes sense because of all the common code), although that point goes up every couple of years as developers add complexity to gain performance. I think the last big jump in "bottleneck performance" was when Marek (pretty sure it was him, apologies if not) moved some of the driver code into a second thread so that the driver could use more than one CPU core. The open source stack isn't quite at the point where complexity needs to go up significantly for a small increase in performance, but it's not that far away either.