even if we did have a software firewall that gave handy popups saying "hey this damned app is trying to acess the net, BLOCK/ALLOW" most of the people described above would just click ALLOW, seeing as most apps we have require an internet connection anyways to operate.

If an app was discovered to do dodgey stuff with our personal data for example, once identified itd be far easier to just remove the app than block its net useage which it would probably require for its normal operation anyways.