"dude........where do I recommend letting anything "rot"...."
You do, you just naively don't realize it.
Museum of Flight is known as one of the rare few museums which actually does care for its exhibits. Duxford is another. Such places are the exception, not the rule.
If all flying WW2 airplanes were grounded, do you seriously think that they'd all be kept in that kind of condition? Please, don't kid yourself. Most of them would wind up as neglected hulks in some forgotten hangar, scavenged for parts or souveneirs. Very few museums actually have the money to care for that kind of complex equipment. The ones which DO have the money have little trouble finding all the stuff they can manage.
If I want to see a lifeless, odorless, quiet hulk I can just look at pictures in a book. Be it an airplane or a locomotive...it has a certain life that you can only experience when its in operation. Anyone who REALLY cares about them understands that! That F6F shakes the ground with a roar that can be heard 10 miles away...you feel it in every bone in your body. The kids scream in delight, men nod knowingly, and women cover their ears! The locomotive's popping valves and coal smoke and the shotgun blast of the exhaust makes for memories that'll last a lifetime. Look at people's faces when their cars stop at the grade crossing and instead of the usual diesel freight train it's a 100 foot fire-breathing monster that rumbles the ground as it thunders past. None of that is possible with a static hulk.
It's about more than preserving the machine--it's about preserving the experience. It's called "living history" and, fortunately, it's a catching trend.
J_A_B