The outer rubber coating on my MXT-400 "mike wire" has recently failed also. Just as an example, my Cobra CB unit still looks brand new even after almost 15 years (and works). So, there is a failure in regard of Midland "quality failure/cheap stuff," I'll also support that claim to a degree.
Yea, I'm still stuck with swapping PL Codes when necessay and as such will look into other radios IF the replacement mike fails from the "poor coating." At my age (and level of use) I really don't think I need to learn another new manufacturer programming plan. But at the time of replacement I will look innto it.