Not if he does the type of job hopping typical in silicon valley. There are plenty of programmers who only stay at a job ~2 years, and never have to maintain a program over a long period. You could imagine such a person saying 'this worked well at my last job' and just keep introducing that kind of pattern to new companies, eventually with '20 years of experience'.

Of course really it is 6 months of experience repeated 40 times.

Agreed. It's "fun" to start breaking your code down into small bits; more interchangeable "pieces" -- until you have to maintain it for 10 years (or worse yet, explain it to a new junior dev) and the extensibility you envisioned never came to fruition and now it's just a liability spread across 8 source files.