if the surface of earth becomes dangerous for humans, what makes you think we can eat the crops grown on these surfaces?

if we dont live in some places accessible to the crops, who is going to manage and harvest and transport it to the rest of the population?

also 1 terrorist attack on the shell of whatever biodome you live in = total catastrophe for all in that doe, simply because we cant survive outside of it.

people can live on places where dates grow. and people can generally live in desert

and the counter is, should the situation of earth deteriorate to the point where humans need to compete with their food for living space, underground/undersea cities will not save you. you are more or less doomed long before that happens. so dont let it deteriorate to that level