As a couple of others have said, in Europe, the Flarm Net system has
essentially set itself up, at no additional cost to pilots. In the UK, we
have gone from nothing, to almost 100% coverage in a couple of years, as
people saw the utility of the system, and just expanded it.

In the UK it is entirely a voluntary system, with both individuals and
clubs able to make their own decisions on whether to install a Flarm,
whether to register it, or whether to carry on as they are. While I've no
real evidence base, I think the majority of private owners have installed
Flarm, but with a lower proportion registering (unregistered flarm shows on
the network, but with no a/c details). Many clubs have also chosen to
install Flarm in club a/c, which both improves safety and allows them to
track the fleet. On the back of this, more enthusiasts have developed
software that allows flight logging (see Jim White's post) and live
competition scoring and tracking (onglide). In the UK it is now normal to
see crews and visitors following the comp either on a tablet or smartphone
or on screen provided by the organisers.

All of this has happened almost by accident. It started with an enthusiast
building a receiver and publishing the results on sites like this. Others
decided to replicate, and the network grew. While many of the receivers
are now based at gliding sites, most are still built and maintained by
volunteers. There may be some challenges in the USA due to geography.
Better solutions might come up, but this is available now, and given the
very low costs, you have virtually nothing to lose. Until you try, you
won't know. If just a couple of those in favour build a receiver, and tell
others it's there, you might be surprised by the results.