Madisar method started as a convenient way to remove the sari if the sage's jut catches fire - either by natural hazard or the agni in the earthern pot aupasana pot got tipped and the hut catches fire. Later this method was reduced to only on marriage occasion. It is both for providing air circulation and quick removal. Pancha Gachacham also was created like that. With 9 yards sari, it also served as a nightly cover for the woman. Anyway, the customs when they are retained, the purposes are never explained for the next generation and eventually only the rituals remain without the purpose. For example, camphor lightening is to kill germs from coughing (Ayurveda) in crowded close quarters, tulsi-water with krambu(cloves) for getting viruses etc., were Ayurveda in nature but incorporated to make them pious so that people can follow it in temples; donation to help poor, naivedyam(pongal etc) to share with the poor members of the society and so on. So, our culture, religion and hygienic principles were all bundled together. As to the color of the saris, only when the natural colors were augmented by synthetic colors, the dark red (Arakku etc) came. The easiest available silk saris had the color and became a norm. Religion never has dictated any thing. It is the time, advancement of technology etc., had created the illusions that some thing should be done according to Sastra when no document can show that. Even Maha Vishnu wanted to kill silk worms to get his Peethambaram is unthinkable. In North India, Krishna wears most modern dress. All right, what is the conclusion. What ever is convenient, wear it. Pyjama Kurta is the Muslim avatar and if that is best suited so be it. No God will punish us as Krishna says” I have given you intelligence and free will” use it. You are responsible for your actions and I do not dictate.
“Karmanyeva Atikaram Asthe”. Religion and philosophy are two different things and leave it to God.