Why is it so hard to buy parts from people

I haven’t advertised on Craigslist for at least 8 years. Facebook marketplace and racing groups on Facebook is my go place. Write up an ad with all the needed info, lots of pictures, ability to share ad in up to 20 groups with a few clicks, and you are set to go. I laugh at how some guys post up ads and then one or two pictures from a 20 year old flip phone and the want 90% of the price they paid for it new, plus shipping. Lol.