The mere fact that we are talking here means that the ToO isn't completely dead. However, I do think that because the ToO is failing to recruit new members, over the long term ToO is likely to decline in activity.

Unless we attract new members,* the ToO will go inactive as members go inactive never to comeback.
Here is another chart:

Y axis is votes in election. X is the election number. This chart doesn't seem to show the dramatic drop off that your chart does. It also seems to predict that the last ToO member will leave around election 40 or so (assuming a linear trend).
If you want to increase there are two things you can do:
Post content, particularly new threads, because new threads inspire people to post more.
Recruit new members. However, I am unsure why a new member would want to join. Unless they love counting or something.