The "loom" theory is very convenient for manufacturers to promote sales of their own cables. To the extent that cables impact on sound quality there is no more logic in suggesting that the same make of cables throughout a system has an exponential impact on sound quality than there is in suggesting that using components from the same manufacturer does so. I don't recall a "loom" theory being advanced in the latter regard to anything like the same degree as I do for cables.
I now have mostly the same make and model of cables in my system but to the extent that the sound quality of the system has improved, it's because the cables are better - not because they are from the same manufacturer.
I think the "loom" theory might "work" for certain listeners particularly where a cable manufacturer has a particular sonic signature (I would suggest Nordost, for example). In that case where a listener is particularly drawn to that kind of sound, then reinforcing it with more of the same might prove attractive.
