You seem to be assuming that a base on Mars or the Moon would have to be a closed system but that is not true. There are plenty of useful materials on a planet

You seem to be assuming that a base on Mars or the Moon would have to be a closed system but that is not true. There are plenty of useful materials on a planetary surface, for example water. There are also many ways to take advantage of a CO2 atmosphere or oxygen from lunar rocks. Even space stations don't need to be fully closed, for example the ISS is constantly being resupplied.