No reason to be a wet blanket here. Mazda has developed something new for their CD. It only activates at cruising speed as well.
https://insidemazda.mazdausa.com/the-mazda-way/technology/mazdas-new-cylinder-deactivation/
https://insidemazda.mazdausa.com/the-mazda-way/technology/mazdas-new-cylinder-deactivation/