It will be iPhone 5S with the same design, slightly improved specs and a significantly higher pricetag.
Therefore, iPhone 5 will stay relevant for at least another year and a half as it will be virtually indistinguishable from iPhone 5S
That's exactly my point.
Every Apple launch will undermine the market value of the previous model so it serves to wait. Why do you think Foxconn has cut production on the iphone 5? It won't stay relevant for as long as you claim since competition has already gained a stronghold on market share.