I wouldn't take lower price for older SoC granted. Usually they are made on older manufacturing process, which may be more expensive to manufacture, also they don't have economy of scale as the demand for them is generally lower. This of course in situation where one is not trying to tap into some leftover pieces. Newer manufacturing process usually means improved power efficiency as well as improved processing power, so going to mid-level reasonably fresh SoC and architecture instead of already abandoned tech IMO has it's benefits. Also, creating PCB with all the other components for old SoC may require more effort and add up costs. OMAP was decent architecture but AFAIK it didn't have much demand outside Nokia and when Nokia went with Qualcomm, TI didn't have much incentive to develop it further. Maybe if Nokia had bought it and made it "their own" like Apple did with their own SoC there would have been a differentiator... but it would have required MeeGo to succeed. So, IMO there are not many good reasons for (really) old SoC if one is to create competitive device.