Is there a point where bitcoin mining will not be profitable? A lot of news accounts are pointing out that bitcoin mining is getting more difficult over time, murch even said recently in chat its getting "exponentially harder". I am not sure if that is the case, but has anyone studied the economics and difficulty/hardness of bitcoin mining over spans of time? it appears clearly &amp; by design to be subject to "diminishing marginal returns". 

Is there a forecast when bitcoin mining will reach "break-even" level &amp; be exactly as expensive as the hardware/energy required to mine it?

I am looking for quantitative/scientific analysis where possible. By the way, its a completely separate question of whether this would mean that bitcoin is no longer usable as a currency. (To me that is very likely not the case.)
It's already here. At present, you're simply not going to be able to mine Bitcoin with consumer grade hardware. Even with ASICs, you're still looking at returns that would have been laughable just a year ago. You're better off mining something like Mint or Aurora, or Doge, and turning them in for Bitcoins. Just my 2400 satoshis.