I think most would be surprised to see that genuine Ford or Motorcraft parts are very comparable in price to some of the aftermarket junk you might find at local parts stores. There is a lot of stuff coming from China made with poor material quality, fit and finish that pass off as OEM replacement. The only aftermarket stuff I'm okay with is some of the Napa premium line parts.
My 2 Cents.
I don't think you will find many Motorcraft Parts comparably priced to what is available at the local parts stores.
Now if you are only comparing to the Napa you mentioned then the price spread is closer.
I can go to O'Reilly Auto Parts, Advance Auto Parts, or AutoZone and get a complete upper control arm for a mm 1 Expedition like I did a couple of years ago 4 32 to $37. Even with RockAuto Ora Tasca Parts, motorcraft is going to be double that.
It is very smart to stay on top of prices though as sometimes certain things will fool you. Many years ago after starter prices at local stores first started to shoot up in price, we were able to get a starter from a local Ford dealer for only about 14 to $18 more than what the local stores wanted.
Remember back when you could get all the GM front wheel drive vehicle starters the 6206 numbers I believe they were, for 39 99?? But then these parts stores decided to crank up the prices on these reman starters. I'm not a fan of the direction the prices are going at the local places as they are basically just charging what the market will bear and all three of them are the same price anyways. Online competition doesn't seem to do much to keep the local prices down as they still capitalize on the fact that people will pay whatever they charge because they want to buy it locally or they want to buy it right now.
So I'm not a fan either way. I just call it like I see it. I see great prices and the quality is just fine, lasting me for many years on things like control arms and ball joints and other front end and suspension parts, brake pads, starters and alternators.
I just did a quick search for the Motorcraft control arm and it looks like it's 75 to $78 online which is right at Double the price I can get one for at O'Reilly. Now I do have a commercial account at O'Reilly and save a small percentage on parts but it's not a lot. It's not even close to 20%. I don't get this discount when I find the cheapest price online for Motorcraft. Now if someone is overpaying for the Chinese built Moog which is in the 50s then yes, you might as well by the Motorcraft but that's not what the post was talking about. It was talking about the ones available at the local parts stores. Yes, the local part stores carry multiple brands but often the most available one that's in stock will be at their house brand and it's also the cheapest.