Some very good and dead-on descriptions here by fellow G body members on what "value" actually means. Sometimes the things you think are valuable are not, and vice versa. It's like an auction, it only takes that one bidder to make or break an auction. Sometimes it only takes that one person who will pay that BIG asking price for your car, perhaps it was identical to their first car, or its what their dad had when they were a kid ect ect, the reasons are endless.
I've been into G bodies my entire life, and a few years back, prior to any hint of a boom on their values, AND against the common senses among this group, I had stated that there will be a time to come soon, when our beloved G body cars will be pulling big coin, three times or more from original sticker price, fast forward to 2022, and that time has come for prime and unmolested examples. I was laughed at the time, but not so much now. It's nice to see because it effects ALL the G bodies in some way shape or form and anyone that owns one, their investment has increased.
Take the Buick GN, few and far between compared to other G bodies produced, and with the asking prices, and ACTUAL selling prices, many people can't get or afford one. So, what do they do, they seek out a Buick Regal and doll it up to look like a GN, so therefore the value of the plain Jayne Regal starts creeping up as well because the market is there for it and guess what, this has happened and IS happening.
The market and value on any item, car, real estate etc. from history and rule of thumb, increases over time. There are many factors that play into value, inclusive of individuals and the exact thing they want or are looking for, if you have what they want, a Malibu with a v6 3 speed low milage car, and if they want it bad enough, they will pay your asking price, because to tell you the truth, it's not every day you come across such a combination, nor fine example as yours. I tend to believe individuals who dispute the prices our cars are selling for, yet will go out without hesitation and buy a pile of plastic for $35K+, that falls apart in 5 years and is worth nothing, are shy a few head bolts to be honest.