What is the point of spending billions of dollars screwing around in space ?

I would think that if there were something out there in space we could use we would of found it by now. Space is/was considered the last frontier to be explored. We have seen it and billions if not trillions of dollars later still havent found anything useful. Does it matter what is on mars? or Pluto? Uranus is a perfect name for discribing space travel since who ever likes watching tax dollars burn up along with astronauts you're thinking with Uranus. Like what was it 280 billion dollars spent to collect some comet dust wow and that comet dust is going to do what? Cure AIDS, stop crime, end poverty? What do they expect to profit off of Mars? Its like beating a dead horse is it not? The planet is dead. Or maybe the scientists plan to hook up some giant jumper cables and jump start it so people can live there?