Yes, some members can make 1 BTC a month. But in order to do it, the best way (in my opinion) is to find a job that pays ~20 USD a day.
Even if you got paid $20 USD per day, you still have to subtract your expenses from that before you can start buying bitcoins. There are people selling stuff online, that makes a lot more than that and these gambling sites and adult porn site operators gets a lot more than that daily. < Well some of them >
There might even be some of the biggest faucet operators, that could earn more than 1 BTC per day. So yes, it does happen, but it's rare.
It's very rare if not putting money twords an investment. Currently 1 BTC is around 600... so to get 600 a month for free is kinda dreaming for most. Even best paying signature campaigns do not reach this area so you would need investments in my eyes.
Now it could be alt coins, mining, etc. It really depends on what your best at. But as I have said bitcoin is not a get rich quick scheme so if your wanting to come here and expecting 1 BTC per month without putting any money in it's very very unlikely. It is hard to find something that could repeat it every month two or everyone would do it... and it would pay less.
Look at mining for example if you make 1 BTC this month you might not next month due to difficulty changes. So you would need to continue to re-invest to hit it (unless you invested much higher at first). But finding something that can do 1 BTC each month is not going to be easiest thing, and a LOT expect it free which just does not happen as BTC holds fiat value.
