The simple fact is there's no need for an app to use Sky Go (or any other streaming solution - iPlayer, Amazon, Netflix, TVAnywhere) on Windows 10. The current browser solution works with the browser included with Windows 10.
Were they to develop a Universal app it would work on (to use your figures) about 1/8 of the target market. Continuing with the browser and it's (potentially) 100% - could even work on Linux and Chromebooks.
There are no apps available for iPlayer, Amazon Prime Video and Virgin TvAnywhere either - surely that indicates that many of the big players see developing a more widely usable solution is a better use of development budget.
Were they to develop a Universal app it would work on (to use your figures) about 1/8 of the target market. Continuing with the browser and it's (potentially) 100% - could even work on Linux and Chromebooks.
There are no apps available for iPlayer, Amazon Prime Video and Virgin TvAnywhere either - surely that indicates that many of the big players see developing a more widely usable solution is a better use of development budget.