Fix for iPhone 11 "won't vibrate" issue
Today I was lucky enough to resolve my own issue of my iPhone 11 not vibrating.
Many may have discovered that the "Vibrate on silent" button under Settings > Sounds & Haptics has been replaced with a new button at the bottom "Pay Haptics in Silent Mode".
If, like me, this still did not restore your phone "vibrate", try this:
Settings > Accessibility > Touch > Check that "Vibration" is toggled on.
This corrected the issue for me, although I had not been able to find any clear advice to this solution online.
Hope this helps some folks!
iPhone 6s, iOS 11