"Why is it that Google products always seem to come out with a bang, only to be forgotten and thrown out weeks later?"

Yeah, Search, GMail, Reader, Calendar, PicasaWeb, Groups, Books... How quickly they all died! /sarcasm

What you're actually seeing is a company that is massively innovating. They throw stuff against the wall to see what sticks. Wave and Buzz didn't really stick, along with a host of other services that don't exist any more, or didn't even make it out the labs.