If there is any life on Mars, we may have to dig much deeper than
whatever the current crop of vehicles there can accomplish to find them.

To restate what I said below in my post on the ExoMars rover, perhaps
we should save up our money and resources for manned expeditions to
the Red Planet to do such things as find life and return regolith samples.
Those kinds of missions will have the ability and rocket power to do the
job properly.

I am not saying that robotic probes haven't done a lot in terms of
improving our knowledge about Mars and elsewhere, but for the
heavy duty questions to be answered, we will need either a permanent
encampment of professional scientists or major improvements in our
technology and AI. I have the feeling the human colony will come first.