It's all supply and demand... and I'm sure there was some crap being released around the time of The Godfather... heck the disaster movie genre started not too long after that. Effects of that genre are still evident today.

However, there are still a lot of "intellegent" films around today. I just watched Mystic River last night and it was excellent. So was 21 Grams. Titanic and LOTR movies transcend all boundries, drawing in people from all age groups, races, sex, whatever - and they were excellent movies, and won Academy Awards.

Hollywood is making more movies these days and it just so happens that a lot of it is silly crap. And they are also going through a creativity lapse with all the freaking remakes and comic books adaptions...

But I am willing to bet that the percentage of of crap produced hasn't changed much over the years.