You are assuming that people buy a new phone every 6 months. While that may be true to you, it isn't true to everybody. I, for example, buy phones every 2+ years. Most of my mates do so every 1+ years. All fanbois buy phones every time Apple releases one* (so, every 1+ years).

I doubt that there will be dramatic hardware changes in 6 months to justify making a brand new phone. If anything, it will probably be better for Jolla to innovate a lot more [hardware wise] in a year's time. Mind you - I'm talking about a proper differentiating new phone, not what Samsung does with their galaxies which is enhance some bits here and there, change the case slightly and charge a lot more for it.

* Except the last time that they released cheap and expensive products. Fanbois in the "first world" will go for the expensive one of course ;-)