I agree that building a debug version of Audacity seems to be the only viable way of investigating this further.
If not, I suspect KXStudio as a possible cause of the problem. Another user on Ubuntu 16.04 found the Audacity 2.1.2 repository version stopped launching immediately after installing KXStudio: https://forum.audacityteam.org/t/audacity-suddenly-wont-open/43023/1 However that issue is not identical because there was some terminal output from Audacity indicating a problem.
Does your other machine have an identical KXStudio setup?
Gale