I came across this page while looking for something related. In my case I needed to be in Verbose mode in Mojave, and it seemed like neither command-s or command-v worked. But I did find an answer elsewhere to the problem.
As was said, using command-r and then Terminal from the Utilities menu will give you single user mode.
For Verbose mode, the significant change is when you have used FileVault, which was the case for my work machine. Instead of letting go of the keys at the Apple logo stage, you keep holding them until you get to the log in stage. Then sign in as usual, and after the log in screen goes away you see the usual thousands of lines scrolling by.