For over a hundred years, all of mankind has attempted the best way possible to buy a/o sell a vehicle.
A hundred years and still nobody has come up with a good way.
There will never be a good way. Just a bazillion variations of the old ways. Damn. What is it about vehicles that brings out the worst in us?
People getting PhD's all over the world wrestlin' with that question brother.
At the risk of being a "nerd" again, its two words: "information asymmetry" ..a well studied economic and social science phenomenon that manifests itself everywhere in our daily lives.
The "fitty-cent" translation of that term is when somebody has, or is perceived by another person to have, better information about a potential deal, that somebody will in fact use their superior information against the one who doesn't have it in order to further their own interests.
Not all car deals turn out bad (and not all people are bad either), but we fear that they might be. So its like we are sure somebody is gonna get "whacked" in the deal, and we don't want it to be us, but we know full well it might turn out to be us, creating more anxiety and/or rancor around the deal.
Buying/selllng cars (new or used) are transactions fraught with mistrust/misunderstanding between the parties and always have been. Next to homes, they are the biggest purchases most of us make, and we all got stories of our own and others who got screwed over in a car deal, or a car repair deal.
Add to all that, they are machines with 30,000 parts so lot can go wrong and a lot of ways to conceal defects, most are not really good investments per se but they are necessities (even for us hobbyists) of modern life, many have incomplete histories (especially used cars)...on and on with the aspects of buying/selling them where we wish we had more information if we need to defend ourselves in a transaction.
Heck, before cars it was horses. Different transportation "technology" obviously, and relatively much simpler versus a car to determine its true condition, but if "Old Paint" came up lame a day after you bought him, and then your field didnt get plowed putting your livelihood at risk, you'd probably be more than a little pissed off at the guy who sold it to you probably knowing it was injured, and pissed at yourself for falling for the smooth sales pitch from the shyster in the first place.
All my ranting is to say I'm kinda with ya and think for a whole lot of reasons there will never be a truly "painless" way to buy/sell cars. As the technology for transacting increases the transparency of deals, the risk of bad outcomes goes down...but we still got a ways to go.