Just a few points of misconception.
Carbon fibre masts, even "snapped" in two, can be repaired relatively easily by any one with knowledge of "epoxy" FRP. The damaged area can quite easily be "sleeved" internally and glassed with very little difference from its original characteristics. Holes can be reglassed similarly. Any "wear" areas can be protected with a thin, small "sleeve" of "molded to the section profile" carbon fibre glued to the area and used as a sacrificial replaceable protector. This thing about UV degragation is no different from the fact that ALL resins break down under the influence of UV, even the hulls of any FRP vessel, - that is why there is gel coat or paint on the hulls of all FRP boats - so the usual way of protecting a carbon mast is to coat it with a layer of clear, two part poly urethare, then there is no UV breakdown, no one would even think of having the hulls of their boat finished in FRP without any paint or gel coat so why would you think that FRP masts should be different?
Carbon masts essentually fall into the same type of construction as the FRP hulls of any boat, just built to different tolerances, so that most of the maintenance and repair techniques that apply to FRP hulls, apply equally to FRP masts. To help give carbon masts a much greater resistance to breakage through impact when dropped or when the cat is "pitched poled" (which is the most common time of carbon fibre mast failure) we have had added a laminate of kevlar as the second laminate in our carbon fibre mast lay ups, this has increased the "toughness" of the mast enormously without adding to the weight.