We will just see more incompatibly between networks. A lot ilke if you have an unlocked cmda phone today.. Where you going to go other than back to verizon? Each phone will end up with custom firmware, so you are stuck with that carrier.
First of all, Verizon is not the only CDMA carrier in the USA. (Sprint, for example, uses CDMA.) Verizon can't "break" their version of CDMA without making it impossible for non-Verizon subscribers to roam on their network.
Second, many of the phones currently available in the USA support all CDMA and GSM network protocols. Some even support them at all of the frequencies used outside North America, so you can roam in other continents.
Third, many phones from CDMA carriers now come with a removable SIM card, just like GSM phones have for years. I'm not sure, but I think switching carriers may involve modifying the apps and parts of the OS (and would that involve unlocking or even jailbreaking?) However, the most important step is to swap out the SIM card with one from the new carrier, and that has become a lot easier.