If you look at the full picture: https://trends.google.com/trends/explore?date=all&q=%2Fm%2F0...
"DarwinPorts" was originally released in 2002. You can see it trending and then the name change which occurred in 2006. It's been on a downward trend ever since.
Even thought Homebrew was released in 2009, it trends relatively constant for the entire dataset. In fact, from 2009 onward, you see a downward trend and then a slight upward trend. So, I'd say, Google is having trouble differentiating "Homebrew" as a drink and Homebrew the package manager.
Now, my personal opinion on the matter:
I used both Fink and MacPorts extensively since around ~2002. I eventually moved to MacPorts because it had better support for Latex at the time.
MacPorts is solid and follows UNIX philosophy in its design. I've been using it for almost 15 years and in that time I've had almost zero issues with either available packages or installation bugs. It's very reliable.
I did try Homebrew. Once I realised it installs user-owned files into `/usr/local`, I tossed it. It's simply broken by design. For more details, e.g. https://applehelpwriter.com/2018/03/21/how-homebrew-invites-...