For the experience.WHY would someone buy an old bike "still in the box" and then ride it?
Just had a thread here a few weeks back on the merits of buying a brand new bike and being the first owner and rider versus buying an identical make, model (and cosmetically identical) garage queen with a few thousand KM on it and saving a ton of money.
"Because I wanted to be the first owner" was the answer. It's not the answer that worked for me personally, but I respect it as something that holds value to others.
And yeah, I'll admit, in this case at least, being the first ever person to start and ride that bike after it sat in it's shipping crate for 40 years would be pretty damned cool.
IMHO just leaving this thing in the crate for another 40 years doesn't accomplish much except to pass it onto the next guy, ad infinitum. A bike was built to ride. Put it together and ride it. No matter what there will still be well documented bragging rights that "This is the bike that sat in a crate untouched for 4 decades".
Someone with a YouTube channel with a big viewership could probably make back the purchase price of the bike in YouTube revenue just making a channel and documenting the experience from taking the cardboard off the crate to the first start to the first ride.