I’m sure I remember going on a visit to Fords at Dagenham with my school once and their proud boast was that they made everything on-site from raw materials. Nowdays it’s all made elsewhere and shipped in. Mrs Motties dad was quite senior on a team at Fords that were making the dash for a new car they were bringing out called a Mondeo. He got some recognition and a wall certificate for it which our son had on his bedroom wall. Took him and his team in the U.K. and Europe ages to do and they were back and forth to Europe for ages on Fords own plane. Just for a dash!Very few manufacturers, make all the parts in their vehicles - I would go so far as to such none of them do. Parts production of many parts is often quite specialised.