My S4 personal phone and S3 work phone are both running cyanogenmod, the S3 is not connected to the internet and runs for a week between charges, the S4 is charged overnight. They both have microSD cards and spare batteries. What more could I want or need?
I will not be upgrading and when one of them dies I will replace with a similar handset.
If a phone manufacturer used their noggin and created a decent handset (swapable battery, microsd, current mid-range specs) with long term support and a yearly cost of say £20 they would take the market.