Surely anyone out in the cosmos reading his message would already have been to Mars, decided it's boring and gone somewhere more interesting.
I think the near-future of space exploration will be unmanned missions. They deliver far more bang-for-buck, even if they are less spectacular as propaganda for space agencies. That said, there was a lot of interest in Rosetta so hopefully the public are getting their head around the idea that we don't need boots on the ground.
Longer-term, the type of ambitious manned missions that we'd like to see are just too difficult to achieve without larger spacecraft that would be impossible to launch from Earth. Ultimately, we need to be looking at assembly in orbit, which will require larger launch rockets or -better still - a space elevator.