If every other variable of the quilt is equal, the physics to this statement does seem to work. A less densely quilted quilt is going to retain more warmth than one that is heavily quilted. This may be tenths of a degree difference, or may be significantly different, I don't know. Probably not worth caring about- quilt what you like.
But it is going to be very rare that you find every other part of the quilt equal. Choose your batting based on whether you want a very warm or less warm quilt. Silk, cotton, poly, wool- they all have different characteristics.