Audacity is by no means a 'Poster Child' for what can be achieved with open source. It does not even do what proprietary audio editors could do more than 20 years ago! The interface also leaves a lot to be desired.
One of the most basic functions of an Audio Editor is to be able to use real-time effects such as EQ and Compression, without these tools, the software is equivalent of a basic text editor without spellcheck, thesaurus or syntax highlighting.
Software such as Steinberg Wavelab had these real-time effects 23 years ago, and it should be pointed out that Wavelab is largely the work of a single developer. As the writer points out, software such as Ardour is probably too complex for someone who just wants to make a few edits to an audio file, however there are many free (if not open source) audio editors that are much better than Audacity (not for Linux though).
I was a Sound Engineer for many years (back when there was a music industry), and I have used Linux as my primary desktop for the last 15 years, so I feel qualified to point out the failings of FOSS in this area - as the writer points out, for the most part the free software available for Linux is amazing, however Audio is still a weak point.