A detail I have had pointed out to me is that at least up until now, the auctions of the 698MHz and above frequencies do not specifically require that devices like wireless mics cease operation in those bands, other than perhaps the public
safety bands. There may be problems if you interfere with the licensed users in those bands but there may also be a lot of this bandwidth that is not used, at least for some time and especially in rural areas.
For example, I believe the Qualcomm bought the
Channel 52 (698MHz to 704MHz) rights nationwide for their MediaFLO mobile TV service, but that may not be active in many geographic areas and apparently nothing would prevent you from using those frequencies as long as that use does not interfere with the licensed user. Some other bandwidth rights are being purchased for future technologies and may be open for some unknown time.
So I don't think that wireless mics operating at 698MHz and above will necessarily have to stop being used. I believe they will stop being sold and their use may be limited if the bandwidth is used in that area, but at least for now (or until the relevant laws change), for some people there may apparently be nothing preventing their use.