I think it's pretty hard to find a horn for much more than 10K, even the custom made ones. My son plays a slightly used Carl Hill and his wife plays a brand new Schmidt and each cost around 10K (maybe a bit more than that), as I recall. And both of them would be replaceable (although in the case of the Hill, it might take some time). Contrary to stringed and some wind (esp. Heckel bassoons) instruments which have appreciated over time and are not replaceable, I believe brass instruments tend to deteriorate with use.
My son and wife are fanatical about their mouthpieces, though. Sometimes I think they'd rather have to replace their horn than their mouthpiece--LOL.
Even so, they would NEVER check their horn while flying.
You're right that brass instruments tend to deteriorate (red rot comes to mind), but really well cared for instruments can last almost indefinitely with some work (such as replating valves). Particularly good individual exemplars though, instruments with high individual and fine sounds, grow in value. Flutes are the most obvious examples. There are people who can do amazing things with a 19th century Louis Lot flute, and some old Haynes and most old Powells are worth far more than new ones. (This is less true as the orchestra tuning inches up past A=442 and the oldest flutes were tuned to A=435 (international pitch) and then A=440 until the past 10-15 years - the newest flutes are pitched A=442 -- but there are a number of top players who prefer older instruments, especially Powells (like my daughter's) that Verne himself made in whole or part.)