The difficulty does not NEED to be ever increasing. In fact there are periods of time where the difficulty is pretty stable, such as mid-2011 to early 2013, or

The difficulty does not NEED to be ever increasing. In fact there are periods of time where the difficulty is pretty stable, such as mid-2011 to early 2013, or the first half of 2015: http://bitcoin.sipa.be/speed-ever.png http://bitcoin.sipa.be/speed-ever.png