I think that the main problem there is that the mac market just isnt and never has been geared towards quick sales and straight to bargain bin prices after a month. Its like that on PC, cos theres new games coming out constantly, but with 12 titles a year from aspyr, theres not as much choice, and so people dig deeper into the archives.
A good example of this is the steady sale of Halo which we see. Now, where is it in the PC charts? nowhere to be seen, but on MGF, you see the demo consistently in the most downloaded. Not to mention that CoD still sells quite strongly.
there must be some way that the game can unlock itself upon recognising the DVD, as with the Steam implementation for half-life 2. you only actually need to log in once a month to keep the game active, but if internet is there it will always connect. So perhaps you only need to insert the DVD once a week? or once every 10 launches? and then you can simply eject the disc as soon as the screen goes blank and carry on normally? of course, this would have to be made clear to the purchaser by something in the software...
and i doubt it does really work too well, if you consider that the downloads from certain sites probably include a crack, or are just the whole disk image... and to go to the lengths of downloading however many Gb to play the game illegally, why would you then not download and install a NoCD patch to make it work?
what works better is demos of games. Some people would justify their illegal download as a trial of the game. I personally did this with Halo, and stuck to it, I bought the game when I got round to it a week later. (if you dont believe me ill take a picture of myself holding the box, a newspaper from today, my passport and wearing a t-shirt that says I love life, and email it to you

) this was about a year prior to the demo being released. had the demo been released I would have played the level I wanted to play, sampled the net game and gone and bought it. As it was, I had to work all the way through to the Silent Cartographer just to play it, and couldnt play on the net cos of the illegal key I had at that point. But I wasnt happy with doing this (i wasnt sure if it would run well on my computer, or if id even like it), and definitely do not condone it in any way. Not to mention that my computer is now far to old to play anything that wasnt out for 2 years, so theres bound to be a demo of it somewhere...
Polytetrafluoroethylene to my friends.
Macbook Pro - C2D 2.4Ghz / 4GB RAM / Samsung 830 256GB SSD / Geforce 8600M GT 256Mb / 15.4"
Cube - G4 1.7Ghz 7448 / 1.5GB RAM / Samsung Spinpoint 250GB / Geforce 6200 256Mb
Self-built PC - C2Q Q8300 2.5Ghz / 4GB RAM / Samsung 830 256GB SSD / Radeon 7850 OC 1GB / W7 x64
and a beautiful HP LP2475w 24" H-IPS monitor