Nvidia released the pricing of the Titan Z before AMD set the price on the 295x2, Nvidia told everyone about Titan Z and it's $3000 price WAY before it finally launched, way way before, and long before the 295x2 was released.
It's also looking increasingly likely that AMD are moving GPU production to GF, leaving TSMC behind, so a 20nm delay at TSMC (well there isn't one), doesn't mean AMD get delayed also. Even if they are at TSMC it doesn't mean a delay. If TSMC(or any foundry) say they are doing a process starting volume production at a certain date, different companies will judge the actual availability themselves and make plans based off their guesses(because most foundries aren't accurate in terms of stating when they will be finally available
). So TSMC say they'll have capacity by say August, Nvidia plan to make stuff for November figuring a 2 month delay but AMD only plan on starting in January because they figure a 6 month delay. If TSMC can provide production before Jan then AMD wouldn't be delayed but Nvidia might. Either way delays for Nvidia around a new process are almost always caused by making a huge core on an immature process.
In terms of an Nvidia "delay", with every delayed gpu release(480gtx for example) they blame everyone but themselves. They blamed TSMC for the 480gtx being late publicly.... even though a half dozen companies had shipped their own 40nm products with no problem, Nvidia would still have you believe it was entirely down to TSMC that one customer had problems and the rest didn't.