Hi Apple,
It's ok, I get it... You're not trying to force Safari down our throats with the popup every couple days... it's just that you didn't have room to add "Don't ask me again" without ruining the aesthetic design.
I don't blame you, I mean look how nicely "Later" and "Try Now" fit together. I wouldn't want to add more options either.
Since Apple couldn't fit it in, here's how to fake the action of clicking on the missing "never ask me about switching to this beautifully designed browser" button. You'll have to open up terminal. Then type these three commands:
defaults write com.apple.coreservices.uiagent CSUIHasSafariBeenLaunched -bool YES
defaults write com.apple.coreservices.uiagent CSUIRecommendSafariNextNotificationDate -date 2020-01-01T00:00:00Z
defaults write com.apple.coreservices.uiagent CSUILastOSVersionWhereSafariRecommendationWasMade -float 10.99
That *should* take care of seeing the pop-up for the next few years...
