A50 is being triggered in March,and I expect it might lead to the value of the GBP and Euro to get worse against the USD. Now it might not happen,but it means there is a chance AMD will be competing in price with discounted Skylake and current Kaby Lake CPUs bought at the older exchange rates.
Ryzen is already delayed from its late 2016 launch and AMD has a history of delays not helping their products at all,and sadly Europe is a big market for DIY computing products.
Plus the longer they delay,the more chance it gives Intel a chance to pull Skylake X forward even for a paper launch.
They need to launch at least one SKU next month to gain mindshare
IMHO. Look at what Nvidia did with the GTX1070 and GTX1080,they released them even when they had not built up enough stock,especially when even the GDDR5X chips used had not even been listed on the site of the company which made them(!),but it gave them the PR victory of launching one month before AMD had anything out.