I pretty much agree with eightbore except I like Smiths a lot more than Parkers (grin).
I WILL however sometimes add oil to a dry parched stock, just enough to blend in and protect the surface.
I'm a car guy too, and have decided that it's the difference in use life. The car has a very limited use life since it begins to wear out from the first moment of use and gets progressively worse rather quickly when compared to the life of the owner. A gun OTOH will normally last several lifetimes if cared for, and so its battle scars tend to be somewhat charismatic and even legendary at times.
How many 100-year-old cars have you seen with original paint and upholstery? If by some chance it WAS original and even stored in a barn, the finish would be long-since deteriorated to nothing. Rotten leather, rusted paint and pitted chrome, rotten tires and frozen parts, rusted engine rings and bearings, rotten gaskets and rubber parts, you get the picture. But a 100-year-old gun is frequently road-ready as-is, needing only ammunition and a preflight checkover for good safe performance. JMOFWIW.
Regards, Joe