Once upon a time, when I was younger, I felt very strongly that I needed a computer with everything replaceable. I wanted to replace a CPU when it got too slow, new graphics card, upgradable RAM, storage, etc. But I found that in the end while I'd make small upgrades, I still replaced my computers at close to the same rate. That because some standard that was built into the old machine was no longer fast enough or wide enough for newer uses, or an interconnect standard changed (think ISA, to PCI, to PCI-X, to PCI-e) The other reason is while i could upgrade some parts, I couldn't upgrade all the parts, and pretty soon those parts were now two or three years old. They were no longer as reliable as a brand new system.

I wonder with these modular phone ideas, if we're looking at the beige box PC industry all over? And whether it will be a good fit to mobile or whether you'll buy your modular system in a year, and then find in another two years that there is a new modular interconnect version without backwards compatibility, and gradually you won't be able to find modules that work with your current frame, so you have to replace that, and maybe the some of your old modules don't work with the new frame, so you have to replace them at the same time. Like a lot of beige bok PC geek, you'll end up with a drawer of old modules in a drawer that you hardly ever find a need for, but you cant bring yourself to throw them away unless they're actually broke. The smart person will just buy all new modules when they replace the frame (that what most people did when they replaced their beige box, because why upgrade but still carry over that old junky graphics card). Pretty soon your at a point where the primary benefit of modularity in not upgrading pieces, but the ability to spec exactly the phone you want when buying. But in reality there are a lot of phones on the market now, and you can come pretty close.

I don't know that this will be the case, but its how I'd bet it would end up playing out.