Men just like collecting. Mint has its place and the ground rules for air rifles is not set in stone but there does seem a head of steam for mint having a premium for rifles from 1980's onwards, or with the introduction of Airgun World 1978. Before that time its on condition. Is that good or bad...? It appeals to some people and not others. Women just don't get it unless it sparkles or fits on their feet!

Modern guns have a certain appeal when new. Probably because the guns don't hold their looks well when used hard. The finishes and general quality was set for the market price rather than longevity. A mint Webley Vulcan MKI in .177 might be worth £250 or more... well I can't find one. Used £75, two a penny.

For those will large collections then not many are ever going to get used. About five or six shooters are enough for the average enthusiast to shoot regularly, just because one reaches for ones favourites.
Whatever floats your boat.