It would hold up as well as its maintained. With poor maintenance it will go out of whack just the same as any other decently made piano would. All acoustic pianos require routine maintenance if you want them to perform at top level for decades. The downfall with some lousy pianos is maintaining them well isn't enough, they turn to crap anyway.
Climate changes are tough on any piano, if one owns a really expensive level piano it's all the more reason to keep it in a climate controlled environment. If one were to spend 150-200K on a nice piano and then sticks it in some back pantry room with no climate control, they deserve what they get back from treating it that way !
There is no magic in the build of an expensive piano, as well crafted as they are, they still are made of wood, metal, felt etc... They don't come with armor plating. Humidity still settles into them, dry dry conditions still shrinks them. They still are susceptible to cracking etc. They are well made non the less, with top components, woods and finishes. That's why they sound so great !