I think Shaun has it about right...plus many people might simply be busy at the moment...I know I am. It happened from time to time on the old forum, even at its peak.
Activity on the old forum is almost non-existent. There have been only 24 posts in the last 24 hours...including some spam...almost none by people who's names I recognise. Also, I doubt whether it is a case of slinking off to the New Google forum. I haven't managed to see what it's like yet, or even see whether it exists. Every time I do a search for SketchUp Pro groups I just get a message saying my membership is still pending.
I'd imagine that the future of this venue gets more secure as each day passes. It's the basic rule of supply and demand...if you can't deliver a reliable service (which Google isn't doing...if only by virtue of all the uncertainty and the way things were originally handled), people will drift off in search of other sources of supply, so that even when you are back on your feet you've lost a good part of your market share. Any new Pro forum will now need to be REALLY good from the outset to affect this one in any way.
Alan