However, workloads in college have been decreasing over the decades.
http://economix.blogs.nytimes.com/2012/01/20/why-students-leave-the-engineering-track/
http://www.nber.org/papers/w15954.pdf
Consider that a faculty member attended undergraduate school a few decades before his/her current students in this context.
But it is not necessarily true that all of the decreased workload is due to decreased rigor. Some types of modern technology have made it possible to work more efficiently. One does not have to go to the library and look through the card catalog or microfilm to write down a list of books to check for the needed information, then go through all of those books (possibly waiting for them through interlibrary loan, or waiting for checked-out books to be returned) like one may have had to do decades ago. Instead, a quick web search may reveal a list of relevant references, then another quick web search will show which libraries have each book, or where the book may be purchased from.
In other subjects, one can also see how workloads are reduced. For example, in a computer science course, it used to be that the whole class would share one computer, with a limited number of 80*24 terminals to connect to it. Now, every student can purchase an inexpensive computer with orders of magnitude more computing power than the one shared by a whole class of computer science students a few decades ago.
For reference, the credit hour system used at many schools is nominally supposed to mean 3 hours of work per week per credit hour, so a full time student with 15 credit hours is nominally supposed to spend 45 hours per week on school work (including both class time and out-of-class time).