This is true only if you don't know what you're doing. And earning $1000 on average per month is not difficult at all, if you do things right and split your earnings between two or three accounts.
I earn no less than $800/mo, and I do that with one site that gets around 100 visitors/day. All you need is the right niche (that has a high CPC). That's it. You don't need 1000 sites all earning $1/mo. That's too much work anyways. I make around $30-$40/day.
Not true at all ! I am earning around $800-900/mo with sometimes less than 100 uniques/day ! It depends on the niche, and whether it's a high-paying one too.
It is perfectly possible to earn that much. You need to produce a useful website that people will like as that seems to increase the amount of clicks per visitor ratio. Then you need link build a lot to get people onto the site. You will probably need around 2 or 3 thousand visitors per day Also picking a niche where there is money to made helps as you will get more per click. If you work hard for a consistent period of time then it should happen for you.