Re: Nothing there...
It's based on stuff having been sent there and not found anything.
In the early 1980s a group of people built a machine. Like various earlier machines of the same type, it didn't work. But the people who built it didn't think it would work: they were building it to find out if it was possible to build a machine like that that did work. They decided it was. Starting in 1990 they built a pair of much larger machines, which took them about 12 years. They were used for a few years, but again, they didn't work. And, again, the people who built them didn't really expect them to work: they were building them, again, to find out how to build such machines. From 2005 to 2015 they built another pair of machines, in the same buildings that had housed the previous pair. On the 14th of September 2015 this pair of machines did what they were designed to do. A Nobel prize was won. But they did more than they were designed to do: the things they found were quite surprising and are in the process of changing our idea about how various important processes in the universe work. These machines are currently being rebuilt yet again to make them better, and together with machines already built in Italy and Japan and others to come they will certainly continue to change our idea of how the universe works.
Here's the thing: there is technical progress. Outside your head it is no longer 1350. Each thing we send to Mars both helps discover stuff, and also helps us learn how to make things work on Mars so we can send better things to discover more stuff. Curiosity found conclusive evidence that there were large persistent bodies of water on Mars, that Mars had appropriate chemistry to support life, that there is currently organic carbon on Mars, that there are varying levels of methane (including some very strange and interesting bumps in the level) as well as a lot of interesting stuff about the atmosphere. It also showed that it was possible to land something weighing a tonne on Mars at all using a previously essentially untested and frankly rather implausible technique. Perserverance will discover new things as it has new instruments, will prepare samples for return to Earth where they can be looked at with machines which it is inconceivable to put on Mars, and has already shown that it is possible to fly a helicopter on Mars so that whatever rover follows it can use one to find interesting and safe places to look (getting trapped in sand has happened and is not good, and you can't find the interesting stuff from orbit).
But I'm sure this is all very boring to you, in your grey empty world.
(And yes: I am feeding the troll. I kind of enjoy feeding them: sorry.)