You, who would rather download 20 complete useless but free apps, than pay 3 $ for a useful app.
I guess, not all of you got your Android phone as a gift from your parents, so you may have payed 500 $ or more for your phone - spending a couple of bucks on an app cannot be a problem to you.
Because chances to make money from developing Android apps are so few, no decent investor will put money into it.
It seems, iPhone owners are more willing to pay for their apps, so in the future, app developers will rather use their efforts in the iPhone camp than waste it on Android.
That means new useful fancy apps will be developed for iPhone, and Android will be a secondary platform with old apps, and that means that customers and device manufacturers will turn their attention to iPhone and Windows.
You may have guessed it, I'm an app developer myself. Last week, I uploaded my keyboard app and a couple of free keyboard layout apps to AndroidPit. Although it is pointed out in the second line of the description: 'layouts are useless without the keyboard app', 20 people downloaded the free layout apps. 0 bought the keyboard app (via AndroidPit).
I am also a user of free Apps, and I don't think I ever clicked on one add link - until now. Clicking adds is the method for free app users to pay for using the app. I have to remember that, and to change my behaviour in the future. Free apps or paid apps is not the question - to pay for the service you get is the question.
Google is aware of the problem and will of course take action, when the trend becomes a threat to their business. One (not very likely) action could be to remove the free apps from Market.