Hm. I dunno, looking at that graph, the 'recovery point' seems to be right about where it would have been without the artificial "Openspace" spike. A little lower, perhaps, but not too far off.

So my out-of-the-rear guess is just the artificial growth - by every avatar with a bit of cash going "OH WHEE I CAN GET MY OWN SIM FOR LESS" and proceeding to load every fancy script they could onto a void sim meant for scenery - has been factored out and now we're about back to where it 'should' be.