The Palm Pre is a different creation beast than the Google Android. Palm gets to have a degree more control over how much memory, CPU, etc is going to be put in the phone. Google is creating a general purpose system that various vendors will 'buy into' and thus has to take their shopping list of requirements (we need it to work on XMb of ram, oh we aren't going to use this CPU, etc).
More importantly the Palm lawyers can say "we are going to be ok with GPL requirements if all this stuff goes to GPL3 or 4 or something" and it covers there production run. Google has to have all the lawyers of the consortium of manufacturers agree to that... and my guess is that is pretty much impossible (even if Google's lawyers was all for it .. which I am doubtful about.)
So throwing out a ton of stuff and using GPL2only and Apache licensed stuff makes the consortium lawyers happy and they get to reinvent years of lessons the hard way.