i don't quite understand why you think that people with 2 yr old hardware can't move to lion? it merely requires a 64bit processor, which to my recollection, is closer to 5 years old. (core 2 duo was released in 2006).
after some research: Every NEW apple mac in 2006 but 2, the "Mac Mini - Core Solo" and the early 2006 iMac had non-64 bit procs.. late 2006 models were 64 BIT procs... so its 5 years.
similarly, i think it becomes fair to stop supporting 5 year old hardware when it comes to the iPhone as well. apple is by far the only company that supports two or three gens back on their phones. i was using a CURRENT model Samsung Fascinate (galaxy s), and it took an extremely delayed schedule of upgrades to support hardware and accessories that were sold by verizon.
putting things into perspective, i think they are trying to advance the "bottom line" by requiring rather new processors. its a bold move, but they drew the line at 5 year old computers, not 2.