This is probably why the Surface Pro 4 and Surface Book don’t have a USB Type-C port

This is probably why the Surface Pro 4 and Surface Book don’t have a USB Type-C port

Versus the newly announced Dell XPS devices that come with Thunderbolt 3 support, on paper, Microsoft's Surface Pro 4 and Surface Book suddenly don't seem that ultimate anymore. Is their lack of Thunderbolt 3, USB 3.1 Gen 2, and USB-C a mistake? Here are my thoughts and some speculation.