The site suggests that if the Xeon "Broadwell" chips don't really bring a lot of performance benefits versus the current generation, and still require a lot of expensive validation work, it may make sense to skip the platform in favor of the Skylake-based Purley platform.
The reasons for the cancellation are unclear, but there are speculations that the giant chipmaker may introduce its code-named “Purley” server platform based on “Skylake-EX” and “Skylake-EP” processors earlier than originally expected. Keeping in mind that “Purley” is a massive event for the whole industry – the biggest server platform leap in this decade – it is unlikely that Intel can really bring the launch of the platform forward significantly. Intel’s clients are working on multitude of custom solutions powered by the future central processing units and chipsets. It is unlikely that Intel can speed-up development of third-party products.