iOS6 and Mountain Lion are software things. We are talking about hardware.
When Apple announces new hardware it's either available immediately, or they give the dates.
Problem is that if Microsoft announces dates, they announce the day Windows 8 will be available for which there is no official date yet. I bet if this tablet was already released and they were to do an upgrade next year on the hardware, they would not mind announcing the date. When the slim Xbox 360 was revealed at E3, they released it a week later in US and this was announced.
I am going to be annoyed though if this is US only release like the Zune player.
Problem is... they still have no clue on how to launch a product.