Spotlight Can't Find Apps

So I recently somehow foobarred my system a little, such that when I tried to use Spotlight to find apps ... it couldn't find apps. This was more than a little crippling as I use cmd+spacebar to flip between apps and now it wasn't finding some of them. I wasn't able to grab a clean screengrab of what it looked like before I fixed the issue, but it looked like this.

Dang.

I took the recommended steps to fix the issue:

$  sudo mdutil -a -i off
Password:
/:
2017-05-31 21:22:15.775 mdutil[25852:15381197] mdutil disabling Spotlight: / -> kMDConfigSearchLevelFSSearchOnly
    Indexing disabled.

$  sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
/System/Library/LaunchDaemons/com.apple.metadata.mds.plist: Operation not permitted while System Integrity Protection is engaged

$  sudo mdutil -a -i on

Password:
/:
    Indexing enabled.

As you can see, I wasn't able to unload the plist because of System Integrity Protection. A quick Google showed that disabling this requires rebooting into the recovery system which ... just sounds excessive for my needs. So I decided to take a peak and see if just "turning it off and on again" was enough, and sure enough:

Success!