No no no
> And now, not even that is true.
You are misunderstanding - Mars' wet past is in little doubt, in fact we are pretty sure it had oceans of water on its surface at one point. This discovery has to do with whether liquid water is _currently_ present, even for brief periods, on the Martian surface. However, due to its now much thinner atmosphere, today water can only exist in liquid form at temperatures up to 10 degrees centigrade, above which it would boil, making the current presence of liquid water rather unlikely. Which is why the original story was so unexpected, and today's rather less so.
It may also be worth pointing out that this by no means implies that there is no water Mars - in fact there is plenty; enough to cover the whole planet to a depth of 35 meters. It's just that it mostly exists as a solid.