You are missing one very important point. Different people want different things, they have different requirements.

If you want a tracking system and you don't always operate in an area with good cell coverage, you need a satellite based system. So some people won't be be able to use a cheap cell based system. With a little effort you can get Spot providing 2.5 minute tracking delivered direct to your server. Presumably the other systems can do something similar. Even the basic ten minute tracking makes a big difference when you start searching for a missing glider.

If you always fly in an area that has cell coverage you have many good options. Phone apps, fleet tracking systems, etc. Low cost and fast update are possible.

Flarm/ADSB tracking is doable in flat areas with plenty of Base stations, but you really need a good group of technical people who are prepared to put time and money into setting up the network.