The "Domino Effect" is applied to created rules. Nonetheless, the first rule will reach all the carts if there is no specific audience defined.
If there is a specific audience defined, it will only reach this specific audience. If there is no second rule, all the other carts will not be retargeted.
As you can see on the following picture, you can see the “reach” of each rule. It corresponds to the percentage of reached carts among all the abandoned carts. Therefore, the total reach has to be 100% if you wish to retarget all abandoned carts.