By that logic every single product in existence qualifies as "off-the-shelf", you're just grasping at straws.
pcs,phones,tablets,TVs most parts are off the shelf. its not a surprise or anything.its common knowledge. in a phone for example,you often hear how the lcd is from lg, the memory is from Samsung, the cpu is from QUALCOMM, the wifi is from Broadcom,and so on. is this not true?
Not only that but you've completely avoided my point regarding the bespoke mainboards.
what about them? motherboards are nothing but boards that have copper traces that connect parts and chips together. Those are designed by the company making the product, yes.