This actually sounds pretty good to me, at least in theory. Upgrading the CPU is quite costly - you have to take out the old CPU and replace it altogether with

This actually sounds pretty good to me, at least in theory. Upgrading the CPU is quite costly - you have to take out the old CPU and replace it altogether with a new one. With HDDs you can put the old one in an external enclosure and get some use from it (if the reason you're replacing it isn't failure), and with RAM you might have slots free, so you can keep using the old stuff in addition to the new. Replaced CPUs tend to be pretty useless. The socket type changes all the time, so you have to eBay it off. Laptops are worse, the CPUs are often soldered on or you can't find replacements. The only real problem I foresee is that the upgrades are likely going to be of limited use. Hyperthreading gives you a modest boost, anything more than that (clock speed, disabled cores, cache) will drive up power consumption and therefore thermal dissipation. Computers upgradeable in this way will have to contain cooling systems that can cope with the extra heat, even if 90% of people will never upgrade. Might still be feasible for the very low end (Atoms - especially as they're so slow even "normal" people might upgrade) or as CPUs become increasingly modular (either double your CPU or GPU cores in the same package, but not both).