I have the same situation,

I left Switzerland in 2013 and came back to Russia. Of course here I use national Russian driving license.

The Swiss one has no expiration date (point 4b). Soon I am going to move to Austria and technically, according to the Austrian law I can use Swiss license lifetime or on a voluntary bases convert it to Austrian driving license WITHOUT any test or exams....

So I have the same question, does CH license still valid after 5 year of leaving Switzerland?))) Is it already striped or not?))) I am a bit afraid to write this question directly to the Swiss authorities, because it might be valid but after my question they will strip it))) ha ha.