R.T. – “If that were true, then they would wear a white on white Tallis for Shabbos, and a regular black on white Tallis for weekdays.”
There is an inyan to have a talis with black stripes. Therefore on shabbos they wear such a talis but hide the black stripes. Some do so even during weekday davening to not be me’orer gvuros. Therefore they wear the tallis by folding the talis under. I have seen gedolim makpid on this (as mentioned, R.Y. of Chaim Berlin, Lubavitcher Rebbe etc.).
I admit that I have no essek in nistoros (hanistoros l’Hashem Elokeinu, v’haniglos lonu), and I suggest you refrain for it too. Kabbolistic concepts are more complex than merely color coded charts and connecting the dots while passing around names of sefirot, shaymos and tirufim.
rebdoniel – the malbush of shabbos should not be the same as the weekday malbush, hence “shabbos clothes” and a shabbos talis. (There is a shaylah if one needs “shabbos shoes” – if shoes are considered a malbush for this inyan, (underwear, socks etc are not part of this cheshbon), v’ain kan mekomo).