Main issue with faucets is:
Faucet owners give a big weight of what their users say, they don't confront them with debates.
A "faucet" (simple script which has a captcha and gives you coins) can and can't be profitable.
If you keep paying high and you don't change rewards when prices swing, you've lost the ball.
A lot of faucet owners don't understand how bitcoin works, why faucets exist, etc.
They have so many tools to understand things, yet, they're not using them.
Google Analytics is the best free tool they can have and decide what kind of rewards they can give.
I don't recommend adsense on faucets. You'll get banned and you'll lose all the money you've got from views/clicks.
Also, most of faucets get a lot of fake clicks.
"I want to help the faucet owner, so I'll just start clicking on the ads". <- one of the main reasons why people get banned from adsense.
"Ordinary faucets" will eventually fade in the future. People should focus on sites with content.
OP is right. This ecosystem needs more ad networks. Bitcoin ad networks, which don't pay attention to publisher sites, if they're "paying" users to come back to visit their site.
I'm working on one right as we speak