the poor orphaned mac pros
come and share your grief if you have an orphaned MacPro
Apple have happily maintained a 32/64bit split kernel for the last two versions of OS X, they simply could have continued this model... in fact the early developers preview of Mountain Lion included a 32bit kernel, capable of running on unsupported macpros.
So in effect they developed the solution and then decided not to employ it.
If i want the upgrades to iCloud which are essentially the biggest changes in ML I need to purchase a new machine, so they are effectively saying that my Mac Pro which has 8 x 3.0ghz cores 16gb ram etc etc is not capable of using the icloud services.