Is it ok to build an immigration base on Mars or the moon? why

Technically speaking, it is entirely possible to establish a base on Mars or the moon. Because whether Mars or the moon, the living environment will be better than the International Space Station, the key is to break through some technical barriers and cost control of space transportation, because in any case, if a large number of people can't be sent out and large bases can't be established outside the earth, the previous energy, food and oxygen must also be supplemented from the outside, so what restricts the development of outer space now is actually transportation capacity.