That should be readily apparent I would have thought given that Apple's A9 can be easily ported between TSMC's CLN16FF and Samsung's 14nmLPE. Presumably the same design rules apply for 16nmFF+/FFC and 14nmLPP.
Still have to tape out two different chips, and as tests have proved, they don't share the same electrical properties (the A9 chips). I don't think there's anything easy or cheap about it .....
Previous poster was also wrong. IBM and GF licensed Samsung 14nm FF ... but IBM never implemented it, and GF now own the IBM foundry business anyway. Also, GF 14nm FF LPP isn't copy exact .. it was originally supposed to be but they used different tools to save money ... hence delays and probably yield / volume / cost issues which got AMD to finally make the leap. Furthermore TSMC has absolutely nothing to do with it. They plow their own (lone) furrow.
TSMC 16nm FF+ and Samsung / GF 14nm FF LPP are completely different. FF+ is a high power process. LPP is a low power (but not SLP) process. So AMD / NVIDIA can't swap around without huge cost, redesigns and headaches ... also this predicates a situation where there is finally a major difference in lithography between AMD and NVIDIA - low power process vs high power process; former is likely to have way higher yields and lower costs .. latter will probably clock higher but suffer badly in cost and yields ... and TSMC's FF+ process will have very, very limited / contested capacity at first, unlike Samsung LPP. Samsung's high power (and refined versions of LPE / LPP) come at the very end of '16, though I'd guess the LPE / LPP revisions will take priority over the HP version as AMD have gone with LP designs.
Q3 2016 is too far away IMO
Carrizo desktop and AM4 will probably be launched and available in April or May. Zen likely launches at Computex with availability as soon as they can get it afterwards - some time in Q3. Arctic Islands at E3 with ~immediate availability.
I think the original plan was for Zen desktop (non-APU) to launch with AM4, before AI, so that people could build a new system before the new graphics cards. It'll be the other way around now.
Either way, that isn't long. Especially when neither NVIDIA nor Intel have anything coming up in the mean time.