I looked at some numbers...in 2014, the best-selling SUPERMAN comic was issue #32, which sold 97,166 copies to rank as the 43rd-best seller of the year.
In 2015, the best SUPERMAN could do was issue #41, which ranked 310th with sales of 55,368 copies.
So in just a year they lost about 40,000 sales from their previous top. It should be worse now.