Get Messages from iPhone onto new MacBook Pro
Per @Tetsujin's comment, I started down the path of what was linked. It didn't work, though. After transferring in the folders/files, Messages looked the same as before.
It got me looking for a similar answer, however, and I was able to come across this article on iMore.
The basic gist of the article is to copy the contents of ~/Library/Messages from the Old Mac into the same directory on the New Mac.
[Insert standard &quot;back up your stuff before doing this!&quot; comment.]
Then, I did a reboot (which I hadn't done with the prior attempt; maybe that was the difference).
Note:
The iMore article seems to indicate that the &quot;Archive&quot; folder is only for conversations that have been closed, and only if you have the &quot;Save history when conversations are closed&quot; option checked. I did not have this option checked, and I rarely close conversations, and all of my conversations were there.
Note 2:
The folders from the original answer in Tetsujin's comment were aliases, and I don't know if they are pointing to the folders in ~/Library/Messages, but – for whatever reason – iMore's solution worked! (Perhaps it was the recommended reboot found in iMore's article.)