Yes, I think I know why. Windows 10 is very picky when it comes to start exe program so putting a shortcut of NCSX in the Startup folder did not work for me either. Searching on this gives this also.
However, I found another way that works for me.
Use the Task Scheduler and generate a task to start NCS X. If the Task should run at startup of Windows you must provide a password for that account. Since I do not have password for the admin account I created a Task that starts at Login instead. When I start or restart Windowss it auto logins to my admin account and now also autostart NCS X.
The slider in the User Account Control Settings must be at the bottom or one level up. It cannot be set so that an applications asks for permission to run.
You are running Win10, but what processor and RAM do you have? I think we need to have a look why NCS Service do not start even in the delayed setting.