There's never been anything quite like Storm, but the counterattacks against the network proved to be very effective. The Storm Network is now believed to contain a few hundred thousand PCs at most, and is shrinking daily because of security software being updated to do just that.
Being noticed means eventual death as defenders adapt.
Cyber-warfare assets are a fleeting weapon, it seems. Better to be prepared to build a botnet and then use it quickly while defenders are unaware than to store it away in the belief you can haul it out and use it at your leisure.