Until I bought a new internal modem and had to work out how to set it up manually I had no idea how to do it either. I would imagine most PC users have never done the likes of this before and are therefore lost because they can't connect. So taking that into account it could be classed as a big deal.
Vista has been coming for ages, everyone knew about it. Any problems anyone has because the software doesn't work with Vista is as far as I am concerned down to whoever creates the disks in the first place.
Its the same situation as the lack of proper drivers for Nvidia graphics cards.
All these companies knew Vista was coming and should have had updated support in place. They clearly didn't.
The trouble is a lot of people will blame Microsoft, who aren't my favourite people but aren't to blame for this as far as I can see.