I think belief in the "founding fathers" comes down to a faith in systems design or the idea that there exists in theory a system which some sufficiently brilliant folks may devise which addresses the enduring human problem of "how do we all live together and get along" in some optimal way. The American system bequeathed to us by the so called founding fathers and refined over more than two centuries was an experiment that its participants and sponsors have largely portrayed as ideal, or at least flawed but superior to others, and always improving.
When a "geek" or systemically-thinking person wakes up politically, having realized that much is going deeply wrong, the first thing he or she is likely to do is to consult the founding documents which most of us were taught in civics class or for our various merit badges comprise the guide and inspiration for our civil governance. Seeing obvious departures from the design, it is not hard to seize onto the idea that to correct things we merely need to return to the design and follow the rules. Indeed that might improve things.
The difficulty of the various struggles to implement substantial changes is hardly an indictment of the system laid out by the founding fathers. Conservatism is the rule. It is wise to temper the passions of the people for radical changes which they may press to address temporary needs. The ultimate success of campaigns to extend suffrage, abolish child labor, end slavery and segregation, and even to rollback prohibition testify to the effectiveness of the system devised. It presumably worked as intended in those instances. It failed to prevent a war between the states, the death of 600,000 men, and much other injustice in more recent times.
One can find much wisdom and value in the writings, thinking and dialog that went on at the founding of the United States and surely a measure of nonsense too. It seems clear however leaders of that time sought to grapple with the problems of governance and cooperation sincerely and with a great deal of intellect and ability. They treated these issues as matters of vital importance in a way that seems quaint and removed from our decadent era -- that is unless you live in one of the many countries lacking material comforts, safety and political stability.
The problems they sought to address have not changed much since then. Human beings are what they are, technology not withstanding.
America is and remains an experiment on many levels. Ben Franklin's remark coming out of the constitutional convention about "A republic, madam, if you can keep it" is relevant today. This surveillance business could be the end of it. So could imperial overstretch and fiscal profligacy precipitating a collapse. Its also possible that the very different demographics of the country two and a half centuries after its founding render it simply ungovernable in the way or fashion imagined by the founders.
With particular regard to the Constitution and its merits, I believe I paraphrase Lysander Spooner in saying, it either has failed to prevent tyranny or in fact provides for it. If it is so, then the verdict would be the same either way. I am not certain I have better proposition but I do not have a blind faith that in order to cure our ills all we need to do is exhibit greater fidelity to the Constitution.
https://en.wikipedia.org/wiki/No_Treason