AOSP follows the "cathedral" approach of open source. gapps are closed and proprietary, that's true, and most apps require one or another gapp. Google has managed to get most apps rely on their services one way or another, even though they published most of the OS as open source. This can't be said for microsoft, or iOS (yeah, the compiler, browser engine and the kernel are open source, but what else?), so kudos to google for this.
Yes, Android is proprietary, but I still like that almost the whole OS is open source. Anyways, I wouldn't want to use the proprietary components anyways, e.g. their maps app, which sends the position I am interested in to google's servers. I use osmand, and have the full map on my device. I don't need to send google my position every time I look at the map, or tell google which route to drive, or etc. Or take the GCM service, which is good in thought, I don't deny that, but I don't trust an advertising company to run it, I prefer to have a free choice over this.
I'm comfortable with the fact that these apps are proprietary. I don't want spyware on my device. I don't want it to be integrated into the system and my ROM creator doesn't care to remove the spyware features. Its already now pretty common among CM users to download gapps onto their phones, even though its illegal, imagine the pressure from the community if the devs removed a spyware component from the open source part that rendered 90% of all apps unusable.