There is a simple way to solve this. Ship the phones without an OS. Then consumers would have the choice of installing Android, Windows, Symbian, or what have you. Ideally the OS would boot from a micro SD card, or at least installed from one.
That would be a huge step back from a consumer perspective, IMHO. The "mobile revolution" is in full effect because the devices have got SIMPLER, not "more open". But I'm sure Stallman and others of his kind would LOVE it...
edit: removed "neckbeards" reference that could sound offensive to more zealous uber-nerds.
When you sign up for an account, you get 2 chips. One is a sim card for your telephone account, and the other is a microsd card with the OS of choice.
I'd bet most people don't even think about the existence of an OS. The software is just part of the thing they bought.
That's a very US-centric statement. In Europe, and other places where border crossings are a daily occurrence, switching SIM cards is a part of life if one wants to avoid huge roaming fees. There's no reason Americans couldn't learn to deal with the same sort of thing.
Moreover, in Europe and other places, contracts are not common and phones can be used with any carrier, so people buy their phones from electronics stores, just like a PC, and then buy a SIM card from a cellular company, then put the SIM card in themselves.
This isn't uncommon for us.