Lambda the Ultimate

Recent Turing Award winner Leslie Lamport's talk at the Build 2014 Conference, Thinking for Programmers. I do wonder if the level of specification (thinking) Leslie recommends here is realistic/necessary in this day of apps, web pages, and mostly non-systems/non-critical programming mostly done by app developers with little to no formal education in mathematics or computer science.

"If you don't start off with a spec, every piece of code you write is a patch".

What do you think, when applied to the programming environments of today (apps, web pages, non-critical systems, etc...). Does it go too far to assume this level of thinking?