VERY true. At least now, after government intervention years back, it is sometimes more transparent. ("Sometimes" and "more", but not always, or perfectly transparent.)
Usually, the last thing in the world to volunteer early on to the sales folks is you plan to pay cash.(This varies by industry, most definitely automotive and RV). Often times they will cut a better sales price in hopes of a nice big bonus/commission/kickback from the financing. Same thing with extended warrantees, dealer added accessories/services (like paint sealant...). There's a reason once a car salesman closes a deal you don't get the keys until a visit to the friendly finance guy!