all the full blouses i've seen aren't like kurtas, they are tucked into the petticoat if they are that long or come perfectly to meet at the petticoat and are tight. i dunno about yall but my kurtas are longer than where my petticoat starts and much looser.
Also the sari was a traditional gown from ancient times when pious women covered their heads with the scarf and their whole body. that's how original sari were, you can read about it in old hindu scriptures. it was shameful to show your skin to anyone other than your husband, with times i dunno how things changed but that's that.