To bump price to the ROOF.
Count yourself, each day, each one get less and less bitcoins. Now 1BTC is a 1,000$.
One year ago, every miner was able get 1BTC so fast, easy, with ordinary GPU, from week to month, it does not matter.
Now you need a special device. Probably, next year you throw it in a landfill.
And price of 1BTC would be so big, cause nowhere you can get it, but buy for $.
And by coincidence, it is optimal periods. Infrastructure around BTC already great, it grow exponentially, like difficulty. By last year, infrastructure, like exchanges, wallets, like coinbase, shops, appear in 10x more than previous 4 years.
Looks like this year - 2014 is a year of bitcoin's infrastructure, everywhere will appear shops, wallets, etc. In 2015 label of Bitcoin will be near Twitter's label, Facebook's label on every billboard on every corner.
2013 - is a year of ASICs.