So worst case, a complete rewrite for a kext in order to support hardware that can run 10.8 would be required. Wasn't 10.8 a complete re-write of Lion, as 10.6 was for 10.5?
Apple could have easily implemented support for certain systems that still technically meet the necessary requirements. Instead, iOS features seemed to be the focus for engineers and Apple can sell more hardware for those who need 10.8 support. Sorry, but this is simply a business strategy by a company that pushes a 3 year turn over rate for their systems (OS X and AppleCare support are evidence to this point).
UPDATE: Thank you MacRumors for FINALLY removing the negative voting system!