Just a reflection rather than a comment, really:

I think it's good that we have this discussion and that it is conducted
that enthusiastically. I even want to thank Don for being the punching
bag here, because he manages to provoke responses with lots of insight.
This threads should be saved as an FAQ list for later reference.

As for myself: having been slightly interested in FLARM from the
beginning, I am getting increasingly convinced that I should buy one,
even though it is not sold in Sweden, which probably also implies that
the number of installed devices it insignificant at the moment...

Seems to be the "Catch-22" like same problem as with the fax machine,
that has been invented decades before its break-through just because
others need to have it in order for it being useful to yourself... All
you can hope for are the "Early adopters".