I think I'm on the same bus with steven r. I don't see X10 changing the CM15A or AHP for a decade or two.
I don't see the AHP/CM15A being available a lot longer. This is technology... it's lifespan is measured in months... not decades.
Four or five years ago the AHP package with smart macros sold for $100 bucks. Today you can get that (with iwitness and OnAlert thrown in) for $39.99. So... what would that price be in a couple more decades? If forty bucks isn't the clearance price... what would clearance price be? Don't forget... what the purpose of clearance is.
I've already picked up my extra CM15A. But when I think about what could be coming down-the-pike with any new (maybe wifi?) technology interface. I will likely find the money for the new stuff (just like everyone else).