TL;DR. Bitcoin profitability is about choosing between buying BTC outright (Coinbase, or Bitstamp) or buying hardware ASIC miners and paying the ongoing electrical fees.
To keep mining expenses low, you will need the cheapest form of electricity. This usually means coal in most regions. "Clean coal" doesn't exist.
10 years from now is a long time, and you should expect additional transaction fees by then, plus many more (different) incentives to mine.
As of late summer 2013 the ASIC market is saturated in my opinion, and the difficulty spikes will continue to reach into 2014. That means the value of BTC must appreciate for most people on the network to get an ROI.
Either one or more of these things will happen:
People will mine coins, pay a lot for electricity, for years to come just to get a ROI
Sell the machine at a loss, invest in Bitcoin
People who buy Bitcoin will cause the price to increase, thus making mining profitable
Mining companies will go out of business (or sell a different product) and whatever ASICs are made now will be the only ones in the game for a while.
Assume that the network hashrate (competition) is so high that in order to make a profit, miner #1 has to mine for 2 years and also wait for the BTC to be valued over 900 USD. (Note: BTC hit $1000 per coin on 11-27-13) After a lot of time and expense (not to mention heat, noise, and an angry wife) he cuts even.
Now assume that in the same time period, person 2 buys BTC at the current Mt Gox rate: $140. (Two thousand dollars worth of coins). The price of BTC only has to increase for him to make a profit.
So the question is
Why are people buying mining machines when buying Bitcoin outright is lower risk and a better reward?
The answer is so they can ride the next mining wave... more on this in a second
The Good News
If you already purchased the miner, you should be fine if the market figures out that buying Bitcoins is "safer" than mining, and has a better chance at making a profit.
Once buying BTC becomes as popular as mining is today, then the price will increase. If the price increases, demand for ASICs will increase as well.
Bitcoin is about riding the wave of either buying BTC outright or buying miners. Each action perpetuates the other, so I'll bet the
mining storm of 2013 will cause BTC to rise and everything will be alright in the end.