All this is accurate. Will also say my 2012 focus was worth 4k in 2019. It's now worth 8-10k because it runs. If I sell it I can't drive money to work. A new F150 jumped 9k from 22-23 so inflation is happening at 20% YOY for that example more on my used car.

Dealerships make money on you by:

Undercutting you on your trade, reselling the trade, selling you a new car, adding in extras like wheel locks, selling special air, moving a vehicle for the manufacturer, and money from the bank for getting you to finance.

The big markups are on parts and labour, so hopefully you come back and get work done (a good dealership will make 1.1x total costs from these two departments) that way car sales are just gravy.

(15yrs dealer experience)