We have spent a great deal of money in the past exploring Mars. A lot more money is planned to be spent in the future. Why? Mars is not much use to anybody except some groups of scientists. Its future value to humanity as a whole is minimal at best. Rocks and sand. Nothing much in the way of an atmosphere. Bitter cold. A very hostile place.
Where we should be looking is Venus. It's too hot!. Yes, it is. But Venus is almost exactly the same size as Earth, so none of the problems resulting from very low or very high gravity will be a factor. It will never be cold like Mars. It can hold a breathable atmosphere. We could colonize an entire planet the size of Earth.
But it's too hot! Well, why? Because of the very thick layer of clouds that covers it. The primary constituent of those clouds is carbon dioxide. So seed the clouds with blue-green algae. They eat C0(2) and produce oxygen and water. The water will condense and fall as rain. It will be turned to steam and sent back into the upper atmosphere, where it will condense and fall again. Each fall of rain will reduce the temperature a bit. Eventually it will begin to hit the surface. As the clouds dissipate and the rain falls, the temperature will continue to fall. Someday there will be an oxygen-based atmosphere and livable temperatures.
Mars is worthless. Venus is the jewel in our neighborhood.