Sorry, cant agree with this at all. Youre talking about the hardcore fans here, not the general audience. A Superman film that draws on the classic interpretations of the characters personality, but updates him sufficiently to the 21st Century would be a surefire hit, especially in todays social climate.
A Superman who fights for truth and justice in a Trump-led world would go down an absolute storm. Sell him as what he is - not some bull**** Christ parallel - but as the ultimate immigrant, whose moral compass and strength of will are absolute... and you make a billion dollars. Actually give the people someone to look up to, and they would indeed join him in the sun.