So you can't explain why a cottage industry of bearing replacement suppliers developed. Nor can you explain why CK provides replaceable bearings. Why Phil Wood does the same. But hey, since I already told you that there isn't a scientific study about it you keep asking for it.

For the OP if they want low maintenance and durability go with square taper. If they don't want square taper, use whatever comes with the cranks they buy and replace as needed with the cheapest option available. One nice thing about external BB is that they are easy to replace and cheap.