Watching the Mars Rising episode Search for Life, there is discussion about digging and drilling as efforts in that search, which will obviously be "scratching the surface". I'm surprised there wasn't more focus on exploring Valles Marineris, the largest canyon system in the universe. Our own Grand Canyon is a history book covering billions of years. Why wouldn't Valles Marineris provide us the same wealth of information about Mars' geological history?

Good point, should get to learn more about our planet. We shouldn't take it for grant like a lot of people to. Maybe this planet has something to tech us humans. How knows if we will ever find out what are planet has to offer us? How knows?

Your information about the Viking life sciences results is in error. There were two life science experiments on the landers. The first mixed Martian soil with a radioactive nutrient solution and looked for radioactive waste gases to be produced by biological activity. This experiment showed a positive result.

The second experiment heated Martian soil and searched for organic molecules. This result yielded a negative result.

NASA, faced with two conflicting test results (like the final mirror tests on Hubble) chose the "safe" one. In the case of Hubble, that was the wrong choice, and it may well be true for Viking as well since later missions determined that the Martian soil contains perchlorates, which decompose organic when heated. Thus the second experiment could never produce a positive result no matter what was actually in the sample.

I worked on the Viking missions, and there was a lot of political pressure NOT to make a definitive declaration that life had been found.