It’s difficult to know the real value of a vehicle taken in trade, the dealer may have simply inflated the value of the truck rather than discount the MSRP of the new vehicle. It’s also possible that your co-worker’s truck was worth more than $22k. A new 2017 Silverado could have cost more than $50k, depending on the exact trim and options.Just for grins I requested value of my 2021 Bolt Premier with 15K miles through Driveway, carmax, and Carvana.
Range was $18K-$22K.
Fellow at work traded his 2017 Chevrolet 1/2 pickup with 150K miles for $22,500.
The only way to find out what a used vehicle is actually worth is to sell it in a stand-alone deal.