They didn't do that and then indicated that a new Mac Pro or something to replace it would come in late 2013 - which is also the current time for the release of the Ivy Bridge-EP Xeon update.
The "late 2013" isn't correct. The flubbed email message was "late in 2013" . It was rather muddled whether that "late" is relative to the then present June or a reference relative to 2013 itself. As in " The Mac is being worked on and a replacement will arrive late, in 2013."
It is dubious to continue to latch onto that flubbed hint email message since it had to be cleaned up by Apple PR later.
" ... Apple PR has reached out and clarified that only the Mac Pro is expected to be next updated in 2013. ... "
https://www.macrumors.com/2012/06/1...c-pro-and-imac-designs-likely-coming-in-2013/
What Apple is saying is that it is coming in the next calendar year. They aren't positioning it within that year at.
Intel's roadmap hints put Ivy Bridge Xeon at Q3 not Q4 2014. Given their recent track record they may announce in Q3 but volumes not show up till Q4 but there is absolutely zero in anything Apple has said, flubbed or otherwise, that they are waiting on Ivy Bridge and planning to skip Sandy Bridge. There is almost no upside in doing that.
Everything at the recent IDF points to Ivy Bridge Xeon arriving some time after the Haswell mobile and then desktops launch over course of Q2.
Ivy Bridge Xeons are sampling now :
"...Bryant said that Intel is sampling both the Ivy Bridge E5 and E7 chips now and that they would be in production next year in the 22-nanometer processes. .. "
http://www.theregister.co.uk/2012/09/12/intel_server_processors_2013/
The 22nm process should be at very mature point by next May June
(defect density chart at end ) and highly profitable to churn out much larger chips.
http://www.theregister.co.uk/2012/09/13/mark_bohr_at_idf/
The only rational reason for Apple to wait on the Ivy Bridge Xeon E5 is that the rest of the Mac Pro won't be ready till 2H 2013 anyway. Releasing a Sandy Bridge Mac Pro in May 2013 probably wouldn't be worth it. Earlier in 2013 it would. Primarily because the Mac Pro is grossly late. Every additional quarter only digs the hole even deeper. Dig too deep and it becomes a grave.