Eventually you reach the limits of thermodynamics then you buy because they won't be anything faster coming out later.
22 nm 2012
14 nm 2013
10 nm est. 2015
7 nm est. 2017
5 nm est. 2019
Not sure how many bitcoins will be left by 2019 though? 21m - 17m (2019 est.) = 4m?

Have you forgotten the halvings or is this just me..
Have you forgotten how technology works or is it just me.
Intel and the big computer companies are just barely beginning to scratch 20 nm in marketable products, their R&D are working on 14 nm. If billion dollar companies/industries take this long to drop nm's, what makes you think bitcoin mining hardware is just going to sail through them?
We'll be at 28 nm for 5 years at least.