I think we have not yet reached the point were smartphones are just good enough performance and capability wise, but we will very soon. Currently, there is very much progress comparable to ten years ago in the PC and Laptop world. But we will reach that point very soon. I am writing this i my 5 year old MacBook and i can remember how slow and outdated my laptop before that (equally old and equally well equipped when i bought it) felt. But today, there is nothing i could not do with this device despite of its age and i still feels quite fast.
We will reach a similar point with smartphones quite soon. Some say a 5 years lifespan for the FP2 is a stretch, but i think it is doable. And i think with the next next model, the FP3, it is more than realistic. And that will make aspects like repairability even more important. I see this as an indication that Fairphone, despite doing the right think morally, is also on a very good track to be future-proof.
My view is similar. I am on a 2009 Mac Pro right now and the only thing that worries me about it is not that its capabilities were too limited, but simply that crucial hardware components might cease to work. When it comes to phones/smartphones, I recently realized how my 2005 mobile phone already had most of the functionality that today’s smartphones have (it played mp3s, it had some online access, it had bluetooth and allowed me to remote control my computer, it had a camera with video capture, it had radio…) – the essential difference being that current smartphones just perform them so much better.
I found that they perform most task good enough already, but not all. I might be spoiled and have very high expectations, but thinks that can still improve are browsing speed, camera image quality, multitasking, network speed and battery lifetime. Concerning the FP2, i think with LTE, 440ppi resolution at 5inches and a Qualcomm quad-core processor, there is only few thinks left to desire. I expect with the next Fairphone or the generation after that (the third or fourth) generation, the phone will be good enough to do almost anything for some years to come.