I always wonder why people consider ADSENSE as revenue generation resource? Adsense is just for starter websites. There are actually other ways to make use of the loyal users following, which will actually make your website a stable and proper business. People really needs to get out of the adsense-hype.
Now that totally depends on what exactly are you doing with your website. let's say you run a forum which is related to computer technical supports. You could actually offer premium membership, trust me, I personally am subscribed to almost 10 forums paying more then $15/month. So it all depends on what you have to offer and how good you are at what you're offering. Also, you could try promoting some local business'es related to your website. For example, one of my friends operating a big fashion oriented website and community, was offered a great amount by "ponds and dove powder/soap".
Its easy money! Paste the code, drive some traffic and you're on! Where with other sources of income like Membership sites, Affiliate marketing, Ecommerce, Services etc etc you need skills to convert, and that is where noobs fail and in that scenario, adsense is their best bet as it is CPC based, they dont have to sell something! But on a side note i agree with you. There are boat loads of different ways to earn from websites, adsense is just one way to do it.
It depends on the time.. some months i earn around 20,000 n some months i dont earn anything... no one can say a fixed amount...
Mine it has not even touched the 200 rs mark in 3 years. I wonder how some people ever make so much money out of adsense!!