We hear some in our society pining for the "good old days", and Donald Trump used that to his advantage in the 2016 election -- promising to "Make America Great Again". The idea is that there was a time (the 1950's) when America was a better place than it is now.
They are referring to a time when this country was ruled by a white, christian patriarchy. White christians (mainly protestants) ruled the roost, and they decided who would have equal rights and who would not -- and who it was OK to discriminate against (justifying that discrimination with religion).
But as the War Babies and Baby Boomers came of age in the 1960's, several movements (Civil Rights movement, Women's Rights movement, Gay Rights movement, and the Counter-Culture movement) combined to bring change to American society. Human rights and individual rights ascended and the "right" to discriminate was no longer recognized by many Americans.
White protestants (especially evangelicals) were horrified by the change, and they have fought it ever since them. But their fight has just worked against them. Their numbers have been going down for several decades now, as people leave the church and religion altogether.
Those white protestants thought they had won the battle, and could turn back the clock with the election of Ronald Reagan and a return to power of the Republican Party. But with the invention of the internet and home computers, that was fairly effectively thwarted.
Although they continue to fight for a return to the white christian patriarchy, their chances of success grow slimmer all the time. That's because their numbers continue to dwindle. The charts above show what has happened in just the last decade and a half (from 2003 through 2017). Note that their numbers have decreased (from 50% in 2003 to only 36% in 2017), while the number without religion has grown substantially (from 12% in 2003 to 21% in 2017). And that decrease has been across the board -- in all age groups, sexes, colors, education levels, and political leanings.
The white christian patriarchy is not completely dead, but it is dying fast -- and that's a good thing. There were no "good old days", and American is greater and freer than it has ever been. We are slowly, but surely, starting to accomplish the American dream of equality for all. And that is helped by the fact that religion has less influence in our society.
The charts above are from a recently-released ABC News Poll -- done between 2003 and 2017 of a random national sample of 174,485 adults.