Bitcoin
will fall. But I'm sure of two things: Bitcoin will fall, and it
will rise. This is just the bitcoin way.
Why do the number of addresses fall every now and then? I would assume the graph should have gone up all the time, no? When people lose interest in bitcoin, I would have thought that they would just uninstall their wallet apps or something. Are they deactivating their addresses as well?
They fall because some months there's more users signing up than others. Whenever bitcoin gets a huge amount of media attention there will be masses more new users jumping on board the bitcoin train to the moon. Addresses cannot be deactivated, but they can stop being used, but this is just a graph of the number of new bitcoin addresses being generated. I expect it to keep rising for the next few months but excitement will die down eventually and they will then fall again.