Fast forward a few decades. Right now NASA has sent many rovers, so have other countries, NASA actually has a couple more planned to get the complete picture. In the meantime NASA is working on their SLS and the Orion spacecraft. A far superior spacecraft and rocket system when compared to anything they have previously had. The SLS is capable of many configurations and hence able to travel as close as an asteroid and as far as Mars, even further. It is NASA’s most powerful system to date. The colossal crawlers, those thing that slowly carry the rocket to its launch position, had to be updated and rated with a higher weight class as part of this far reaching project.
So have some patience, NASA isn’t resting on its laurels, it has many on-going projects in place and has always believed in redundancy and precaution and look what it has accomplished! It will make its move and when it does, the time will be right!
Now that is not to say that Denis Tito shouldn’t get us rolling with a Mars fly-by. If Inspiration Mars can help NASA get to the next step. NASA is currently in talks with Inspiration Mars and seeing how they can collaborate on mutually beneficial aspects of the mission areas such as: spaceflight, space-technology and Mars exploration.