The issue is not the invention of the dotless I, it already exists, the issue is that the took a vowerl , i/I, and the assigned the lower case to one vowel, and the upper case to a different one, and invented what left missing.
It's like they decided that the uppercase of "a" is "E" and the uppercase of "e" is "A".
It's like they decided that the uppercase of "a" is "E" and the uppercase of "e" is "A".