The problem with every activation scheme is that the company (developer and/or publisher) needs to continue to exist for you to be able to install the game, and possibly to play it. Even if they are still around, they may decide to drop support at some point.
Then they can release a patch or they could simply build an activation termination date inside the game itself so it will not require activation after a specific date.
It's very easy to do and VERY secure from crackers, hell it's easy to build as well.
Protection no matter what kind will never stop theft. The point is to keep the game as secure as possible for as long as possible.
Activation achieves that far better than anything.
On top of that they can get rid of the useless overzealous cd protections.
