In a major endorsement for Multiview as a must-have feature for sports fans, Comcast has expanded Xfinity Multiview to millions more US consumers, by launching the feature on a swathe of additional X1 set tops. The US operator has not revealed the exact scope of the expansion, but the announcement infers that the full Comcast X1 subscriber base can now access Xfinity Multiview functionality. End users can view up to four live games simultaneously on the same screen, with this expansion strategically timed for the NCAA basketball tournament. Over in the UK, Comcast-owned Sky introduced Multiview functionality last year for select content. So, with mobile-first features finally making the jump to the big screen—why did things take so long, and…