Chanel was quite certainly not designing waistless dresses from the beginning of her dressmaking career (as evinced by the plate below), and of course the "stifling" Edwardian costume was gradually evolving on its own. Fashionable dress was much looser at the waist, but still frequently had a defined waistline, and even Chanel partook in the general complication in decoration and fastening that fashion involved at the time.
|"Jersey Outfits; Designs by Gabrielle Channel [sic]", Les Elegances parisiennes, March 1917|
|Good Housekeeping, September 1918, p. 9|
|Boston Symphony Orchestra Program, 1917-1918, p. 1274|
Jersey is part of Chanel's story, but the trouble is that the way it's usually presented as her sole discovery combined with the fact that much of our clothing today is made of knits implies a far greater influence on her part than exists.