Actually, they are phasing out the cpus that power the two top end consoles, and I am not sure what having GCN in consoles has to do with Zen cpu performance.
If you are talking about dgpus, I think they have a good chance to gain back a fair amount of market share. It just depends on whether they introduce a new lineup of more efficient cards. If they only introduce one or to top end monsters and the rest of the lineup is rebrands, they are screwed, no matter how much the AMD fans on these forums will love a top end powerhouse and will tout price/performance for the rebrands. They need a whole new lineup with more efficient cards top to bottom, no matter how much some people like to deride efficiency.
As far a Zen, even if it is a technically successful product, at least until 2017 or later, they are betting the farm on servers, because by not including an igpu, they are ceding basically the entire consumer and enterprise market to intel except for high end desktop users.