Following that link for the Microsoft Visual C++ Redistributable 2013 (version 12.0.30501) files now gives "We're sorry, this download is no longer available.". Strange, as I was just able to download them a week or two ago.
I made the mistake of quickly reading the OBS Studio Installer dialog box and only downloaded the x64-bit version.
I contacted their support, but they said it was not available internally either (what from I could understand from reading their loosely-worded response), and that it was possible their engineering team had to do something with it.
So, I searched my filesystem, including my Steam game folder which I recalled usually had many of these installs run for my library of games. I actually found the 2013 redist files in my install or EA's Origin in its root folder, and they allowed the OBS Studio to progress!