Sprint has always been the closest of the US mobile operators to the cable sector and now it has added Cox to its list of partners, joining a recent deal with Altice. This is the latest chapter in a long saga of partnerships, which have never – so far – delivered as much as they promised to do. There is clear strategic logic to a tie-up between mobile-only Sprint and the wireline cablecos to form a fixed/mobile platform to challenge the big telcos’ quad play offerings. A decade ago, Sprint had various deals – with varying levels of success – with the main cablecos, including co-investments in WiMAX, the failed Pivot fixed/mobile venture, and the SpectrumCo arrangement to bid in…