You are viewing NASA in a very idealized manner.
NASA has been a schizophrenic institution from its very inception. Allegedly NASA was a public institution intended to demonstrate this country's strength in its space endeavors. It was never intended to be cloaked in the veil of National Security. However, our competition with Russia on idealogic ground also demanded that we hide our advancements and technolgies from Russia during the cold war.
NASA's own structure is schizophrenic.
JPL's funding and reason for being focus on non-manned missions into space. You're correct in believing that the discovery of artificial relicts on Mars would fuel public attention and thereby funding for missions. However such artificial finds would likely lead to a call for manned missions and loss of funding to JPL.
However, this overlooks the fundamental problem of the effect of discovering evidence of artificial constructs on a neighboring planet, not to mention the fact that these artificial constructs show immediate, current activity:
I reference my own posting here:
"If The President Is On TV, It Is Far Too Late!"
We live in a society fueled by the speculative economy of persons savings and retirement monies being inexorably tied to the fluctuations of the Financial Markets, The Stock Market. Investment in this stock market is the life-blood of virtually all American companies, both large and small, and provides them the ability to operate, grow and expand. This market of investment ties America with virtually all major economic markets all over the world. We SEE the import of this market on every evening news broadcast, in the policies of that .. President.. and his selection of advisors..and we feel the decisions made involving these markets in our prices in the grocery store and most alarmingly of late, at the gas pump.
These prices are not just based on "realities" but are based on emotional responses of the purchasers.. the investors..the market itself. Sometimes these emotions are bad only because a company did not meet its projected expectations. Sometimes these emotional responses are overly GOOD, like the amazing soaring prices of "tech stocks" involved in the internet and its amazing erupting market of "unbound potential", despite these companies not even operating in the black, having no profit whatsoever.
You might ask yourself what do these things matter to what's on Mars? Well, in 1929 banking itself was growing into prominence and it too was relying on a similar "money multiplier" that the stock market employs in its lending policy of persons .. SAVINGS. Some loans were going bad and as a result of troubles in the farming community and this led to persons losing faith in the banks and an overall rush on the banks for their own personal monies. The end result was not only the Great Depression in the united states, the desolation of a large swath of farm land that became known as the "Dust Bowl" but also an economic crisis of global proportions that effect the world and contributed to the World War.
What is present on Mars has the ability to lose the populace's faith the Government's ability to protect, loss of faith in and demoralization in religions..and lead to an overall panic and "hoarding" of everything from arms to food supplies and removal of monies from the GLOBAL stock market that has more reason to cause serious social and economic collapse than that stock market crash of 1929. The worst imaginings of "Y2K" catastrophe are a cake walk in comparison. Not only would the economy collapse, but food and fuel distribution systems would fail..and petroleum would become an even scarcer commodity.
You think I am kidding but I am not. Already in my postings I have made mention of a Presidential Executive Order made by Clinton in February of 2000 that removed the previous state of "Martial Law" including its Military Tribunals or "military court" in the event of a National Security Crisis. The removal of this military court was done with the implied suspension of all civil liberties in allowing any and all persons to be imprisoned without reason, for any duration. This was obviously intended to be used in only a worst case scenario involving total economic collapse. However Clinton obviously viewed this legislation as such an immediate need that he pursued it immediately after having been impeached, when he was a "lame duck" President and should have been more concerned with cleaning up his legacy.
You and many, many others need to shed their naiveté if they believe for ONE MOMENT that the news of the Truth of what is on Mars and elsewhere is EVER going to come via any President over a publicly held broadcasting company or news agency ( OR NASA ) until absolutely unavoidable and total hysteria of a cataclysmic event which was unable to be "spun" or disguised has already caused severe harm.
NASA IS the Government and DO NOT expect NASA to discuss these FACTS until it can has no other choice