If AMD has a part with 6C/12T, Haswell-level perf/MHz, and can achieve clocks similar to Haswell, $250 is not a realistic price point. They would charge more.
When AMD was in the lead and released a $1000 CPU, intel came in and undercut them by half!
Just because someone charges a certain price for something doesn't mean it's actually worth that. There is always a tax associated with owning the "best".
Intel is living in the past. 6 core CPUs won't be unique unicorns anymore... Dual cores are nearing obsolescence, and we have been stuck on quad cores for the mainstream market for like a decade.
A 5820k could be had on sale for $300 TWO years ago!!! Assuming Zen can match it's performance, why would you believe it would be worth more than $250 today!?
So let’s have a little fun with this and pretend it’s accurate. Nothing happens in a vacuum and AMD has to provide better bang for the buck to get back market share from Intel. I tend to buy midrange systems so I would be most interested in the XP 613 at $240. If we go to Newegg, what can we get at that price? At $243 we have an i5-4690. It is Haswell which helps as Zen is supposed to have Haswell like performance..
Old PC parts often go up in price after they are discontinued.
I was looking up 5820ks awhile back, and 2 years ago you could catch them on sale for $300. Nowadays, they go on sale for about $340.
Looking at PCpartpicker, the 4690 could be had for about $220, and as low as $200.
http://pcpartpicker.com/product/WsR48d/intel-cpu-bx80646i54690s?history_days=730