Thank you for documenting your experiments.
Had you installed older versions of Audacity before? The known cause for Audacity 2.1.1 not launching is presence of an audacity.cfg settings file from older versions of Audacity. The workaround of modifying or deleting audacity.cfg is described at Fix for Audacity 2.1.1 not launching and near the top of the 2.1.1 Release Notes.
The problem as described above is believed fixed in our source code so should not be a problem in the next 2.1.2 release. It was a problem of writing the “socket” file Fix bug #1087 · audacity/audacity@2a6d423 · GitHub.
Yes Audacity is executed by a shell script inside the app bundle. If you rename Audacity.app/Contents/MacOS/Audacity to “Audacity.sh” the script becomes a non-executable text file and Audacity won’t launch.
I see 2.1.1.0 here.
Let us know if this was the first time you had ever used Audacity. By the way, although it can be useful to experiment with beta versions of operating systems, Audacity has no explicit support for that and I recommend you use the released OS for production work.
Gale