It is immediately obvious and apparent that there is one particular user here who is uninformed about the structure, mechanisms and "building blocks" that comprise the Internet protocols and how these protocols interact with the components in use at the receiving end and I would recommend he acquire, read and study a basic introductory text on digital communications. In particular I reference his remark "invalidates the entire argument that cables or switches can make a difference" as erroneous, misleading and misinformed as has been sufficiently and amply explained by others who have specific, relevant, applicable experience to the matters under discussion.
One problem I often and frequently observe is that those who make such claims, arguments, and assertions have a "feeling" that science and engineering should be "intuitive" but that is not usually the case until you have gained advanced knowledge, skill, and understanding and have combined those particular achievements with actual real world experience.