In this post I would use Perfview /ETW to diagnose the delayed start-up of visual studio.
To analyze the problem start-up VS within Perfview as a run command[gist https://gist.github.com/naveensrinivasan/5eb6406d6d38f2143acb]
This would launch visual studio and collect etw traces. I have also enabled CodeMarkers , which is ETW traces for Visual Studio in case if you want to trace any extensions performance.
The reason for that is perfview groups call-stacks for better viewing. I cleared the “groupparts” textbox and then expanded the start-up thread.
Perfview is great tool for identifying where the time is being spent!