Towards a line 19 between La Défense and Paris CDG?

What if the Grand Paris Express included a line 19 between Nanterre and Gonesse? Valérie Pécresse and the Val d'Oise want to believe in it. Business travellers would be able to reach Paris CDG from La Défense.
line 19
The project for line 19 was presented on 22 November. Its authors hope to have it ready by 2040.

Go to Paris-CDG directly in metro on leaving his office at La Défense That's a promise that should be of interest to more than one business traveller... The 22 Novemberhas gained further momentum with the announcement of Valérie Pécresse. The President of the Île-de-France Region andÎle-de-France Mobilités on Wednesday unveiled the project for the line 19which would be part of the Grand Paris Express.

This "super metro" between Nanterre and Gonesse should travel between 25 and 30 km in total. It would serve nine to eleven stationstruly integrating the Val d'Oise in the Grand Paris Express whose Department...