Inadequacy of Classical Music Swaras

I've had some basic training in Carnatic music. I've also been a karaoke singer in local karaoke clubs....

One thing that occurred to me when I studied the syllables ('swaras') of classical music viz. Sa, Re, Ga, Ma, Pa, Dha, Ni, Sa representing different pitches ('Srutis') was the following...

You 'spell' these syllables by progressively moving your tongue on your  palate from just behind the front teeth backward to utter 'Sa', 'Re' & 'Ga'. After 'Ga' you utter 'Ma' & 'Pa' with your lips, then go back to your palate for 'Dha' & 'Ni' progressively moving your tongue backward as earlier. So the first THREE music syllables are on the palate, next TWO are on the lips and the next TWO are on the palate again.

 Why did the music gurus choose that way i.e. use only 7 syllables (or 'srutis') whereas symmetry demands 8. (The fact that the basic colours in visual light are 7 viz. Violet, Indigo, Blue, Green, Yellow, Orange and Red doesn't justify sound to comprise of only 7 pitches or 'srutis')

So the music syllables must be 'Sa', 'Re', 'Ga', 'Ma', 'Pa', 'Dha', 'Ni', '?'. So 8 in number. The last syllable can be named as 'Sha' which is produced by moving the tongue further backward on the palate after 'Ni'.

Or in other words what I propose is that instead of designating the next sruti after 'Ni' as 'Sa'   name it as 'Sha'. The sruti of 'Sha' will be that of the present upper 'Sa'. The sruti (pitch or frequency in the language of Physics ) of starting 'Sa' of next octave will be the sum of that of 'Sha' and that of starting 'Sa' of the previous octave.

Note that we speak of 'OCTave' to refer to the set of EIGHT upper srutis and NOT 'SEPTave', as it were...

Aside from the theme on which I wrote above, I found an interesting fact about the frequencies that are representing the Swaras and about the rate of increase in frequencies as we proceed from 'Sa' to upper 'Sa' in the middle octave. ( There are 3 octaves in music... Lower, Middle and Upper) The frequencies start from 240 Hz to 480 Hz in the middle octave. The interesting thing is that the frequencies increase for the swaras (in all octaves) in the ratio 9/8, 10/9 and 16/15 for 'Sa'-'Re', 'Re'-'Ga', 'Ga'-'Ma'  then 9/8, 10/9, 9/8 and 16/15 for 'Ma'-'Pa', 'Pa'-'Dha', 'Dha'-'Ni' and

'Ni'-'Sa'. 

I wonder why the consecutive swaras couldn't be assigned values that result in constant frequency ratios between them!!!