Mining Hardware lifespan is less than a year? I have been exploring mining hardware at http://mining.thegenesisblock.com today.  No matter what hardware I look at, all of them are making no profit by Oct 2014.

How is this a good purchase?  I assume the answer is that if you spend 5K on hardware and electricity and make 60K back in bitcoin in a years time, then you can consider it a good purchase (even though the hardware is now losing money).

Also, how is this model sustainable?  Will new hardware be developed fast enough to continue mining past the middle of 2014?  Am I reading too much into that prediction tool?
Mining really can be a zero sum game. The profitability factor though is the potential of increase in Bitcoin value. If you start mining now and begin start to mine less and less, you may only come out even. Hold those coins long enough, and you may be able to make a profit if the value of Bitcoin continues to increase.

If you throw all this money at ASIC hardware and it becomes useless in a year, it's trash. There is no use for out of date ASICS. Invest into GPUs and CPUS, in a year, you can at least sell the hardware.

Personally, I feel as though there is more potential for growth in GPU and CPU coins such as Litecoin and Primecoin/Quark. You can mine these coins and transfer to Bitcoin if that feels right for you. I started mining Litecoin in June with the assumption that I would break even around January. The value of Litecoin skyrocketed and the whole deal became very profitable. It all comes down to whether or not you believe cryptocurrencies will continue to grow in value. I believe that cryptos are just in their infancy, and things are just getting started. You might also be better off simply buying coins.