Declinisms share some traits. They have more purchase in times of turmoil and uncertainty. They are also prone to thinking that the circles of hell can be avoided only with a great catharsis or a great charismatic figure.
But most of all: they ignore signs of improvement that point to less drastic ways out of trouble. Declinists have a big blindspot because they are attracted to daring, total, all-encompassing alternatives to the humdrum greyness of modest solutions. Why go for partial and piecemeal when you can overturn the whole system?