Too much money is being spent on answering a philosophical question and as long as there are billions of dollars in budgets, scientists will continue to look for those damn bacteria under the rocks: "they must be nearby, we just need one billion more and another fifty years". In the meantime, we continue to use propulsion systems developed by the Nazis. Mars is full of holes, tomorrow something like the one that fell in Hellas could reach us... And only the Martian bacteria would be left to start over. We need a new nuclear-powered electromagnetic propulsion system that is powerful enough to deflect an asteroid or shorten the flight time of exploration probes.It's NASA own fault...
They took the most complex mission architecture for MSR
A rover that take sample and drop them on Surface, otherwise the radioactive power source could alter the sample.
NASA has to send Solar powered Rover to collect those samples and bring them to Mars orbit launch system
what launch into orbit were dock with Ion drive Spacecraft that return the Samples to Earth
Means four spacecraft to build and launch and operate, what explain the US$11 billion program cost.
(The Rover of the four already active on Mars)
There were alternative propose in 1990s by Robert Zubrin.
Small Rover and Return craft with Methalox plant launch to Mars
After landing the Return craft produce propellants for return, while rover collect samples
once ready, the Rover load them it into return craft, who launch direct to Earth.