I think the difference between Ubisoft and other publishers is that they use the "Starforce Pro" version.
In the "Pro" version of Starforce everything is blocked by the protection, like "Daemon-Tool", "Alcohol", and Software-debugger like SoftIce and so on...
And the "Basic" version only does couple of that things.
You can read about this here->
http://www.star-force.com/protection...on.phtml?c=310
So i think that's why some games could be cracked in a few weeks and others want be able to get cracked for a year or even more...
For cracking games, a Software-Debugger is high priority and even if there won't be someone who programs a NEW, ULTIMATE, UNFINDABLE, HIDDEN Debugger, the way cracking the Pro version of Starforce would be very long stony and hard.
Greetz!
thE reaL M.A. Rapman