The rule of thumb in space travel is that sending a human costs 1000 times as much as sending an unmanned craft for the same mission. Add on to that the fact that going to Mars would be an INCREDIBLY stressful mission for a human taking a very long time to get there, would require tech we don’t have yet (but is being developed), and would be incredibly risky too. It will happen at some point, no doubt about it. But man we are not there yet.