What are cash outlays & expected inflows for an individual miner?
There are a bunch of mining profitability calculators here. You just need to fill in how much you're going to spend on the equipment, what sort of hash rate you get from the equipment, how much you pay for electricity and what you think bitcoin will be worth and it'll tell you. These are all highly dependent on what you buy, how much of it you buy, where in the world you are and what bitcoin price will be. Investment yields will differ based on those factors.

An ASIC machine manufactured 2 years ago in Paris is going to be much less profitable (or basically lose lots of money) vs. getting a bulk discount on the latest ASICs in Iceland.

Also, this is a question that gets asked quite often.