

No, those salts don’t affect satiation at all. They just affect taste. The satiety part has to do with food bulk.
Potatoes are a good example. Very high in carbs, like Doritos, but also very bulky. The bulk makes you feel full, unlike the Doritos, so you cannot eat a huge amount. Potatoes also don’t come with the flavour enhancing salts so people don’t want to stuff themselves anyway (unless they add the ingredients themselves, such as with loaded baked potatoes).
I believe a prison actually experimented with this. Gave the prisoners all you can eat plain boiled potatoes with nothing to dress them up. The prisoners actually lost weight because they only ate enough to feel full, not to gorge themselves. On the other hand, rats will become obese on all you can eat Doritos but not on plain rat food.
Evolution is not our friend. Evolution favours reproductive fitness, not happiness. Happiness is just one of many tools in the toolbox for getting us to reproduce.
The current situation with low birth rates due to the availability of contraceptives is a temporary blip. Right now you can witness a wide range of forces arrayed against that status quo. Note that for humans, evolution operates not only at the genetic level but also at the cultural level since parents can pass their culture on to their children.
We’re witnessing a major backlash and reaction against secular liberalism, a return to authoritarianism and a revival of religious membership. Religion has always been one of the most powerful of evolution’s cultural weapons for increasing reproductive fitness.