Well the install data could easily be put in a demo and its not a bad idea cause most people don't do anything during their downloads. I for one tend to watch a movie or listen to music while I surf the web on my laptop. But for those people who don't like the installs you don't get how sony is compressing the files and during the install it is uncompressing everything. Microsoft might have their stuff uncompressed. But what does that mean if sony started leaving their stuff uncompressed? You would end up spending more time downloading the game which would the extra time would probably be more than the install time you hate so much.
And for those people who think that the install is just copying files off the BD I believe you are mistaken. I have 2 facts I would like to point out from my expirience.
1. Installs usually entail that there is a process of uncompression going on. This means turning smaller files into bigger ones so things load faster and don't hog the processor while being run. This happens a lot in gaming. (for example GRID for pc is a 6.5gb download yet when installed it takes up 10gb of data on your HDD)
2. The install process probably handles many small files. If you ever used a flash drive to copy data you should notice how copying one big file is a lot faster than copying multiple tiny files that total up to the same size.