So I would disagree when you say it's "not really your job" and "just plain stupid". Our job (as developers) is to create a product that helps our clients navigate a very tricky business environment -- one which most people have never experienced before working here. The time frame of the initial support training and continued learning is justified.
That's not to say that our system's perfect, mind you. In the 6-plus years since I was hired the company has gone from around 25 employees to almost 100. My initial training before actually taking support calls lasted about 4 days, then I was thrown into the fire. The current new employees spend like 3 weeks in the classroom before ever picking up a phone, which I think is far too long.
That's been my experience when I've sat close enough to hear support calls (although in my case it has always been because of small offices, not because of any deliberate attempt by management to make developers more aware of real customer experiences).