Yeah, calling it "The Five Year Itch" is a great way to alienate anyone who hasn't worked in the same job for 5 years.

Also who, when bored with their current job, asks themselves "oh how could I scratch this Five Year Itch that I'm having"? I'd venture to say anyone who has worked that long in software development would either reach out to their network or simply stop ignoring the requests from recruiters they're getting.

The other side of their market is employers--even if accurate, I'm not certain that pointing to a inch after one year is helpful.

More generally, a name of with this sort of specificity gives people a chance to paint themselves out of the picture. Regardless of the duration references, some of the relevant audience is likely to say "that's not about me".