I'm not convinced that software has been increasing in complexity, I just think that more complex sites are being created now than in the past, and there are less capable developers having to work on these sites.
I agree that pressure is high and time constraints are tight and this forces people to look for an answer outside of themselves.
This is the "if all you have is a hammer, everything looks like a nail" kind of view.
What i believe is, the complexity of developing software has been increasing and we have a lot of pressure specially due to time constraints that we are always reinventing the wheel in order to meet deadlines and try to make things easier.
And the result is always the same: bloat.