I agree about writers getting worse as they go on. it seems to happen to many and it's always sad. I'm loyal: it usually takes me wading through too many bad books before I give up on an author.
The saddest for me was when one of my favorite authors, Dorothy Gilman, went downhill. I love her books. (No, maybe tthe saddest was Agatha Christie).
Interesting about craig Rice. I'll have to try to find the ones I read as a child (with children as the detectives) and see what I think. Maybe my grandchildren would like them. Now there are more mystery series for children. In my childhood, these were the only "whodunnits", I knew (Nancy Drew and the Hardy boys were a slightly different format).