For better or for worse, this seems to be the AMD promise through and through as the same thing is said about their GPU's..always tipped to be better in the long run, but never at that moment.
Personally I think AMD need to focus on delivering products that deliver the performance now and today, not at some point in the future when their rivals have just released something faster anyway.
Zen certainly shows a lot of promise though and I am looking forward to their 2018 revision where they can hopefully up the IPC, clocks, overclocking and game performance a bit to make it a true rival for Intel's fastest.
The best thing about Zen is the price and the fact it has clearly made Intel think twice.
It makes their current X99 platform prices look pretty expensive.