Priorities priorities priorities.
Andre Staltz gives[1] an approximate deadline of 5-10 years, or we're doomed.
[1] https://staltz.com/a-plan-to-rescue-the-web-from-the-interne...
We should be focusing on tech that makes aerospace less costly. The benefits will extend beyond a free & open network. There is good science and theory on ways to reduce costs in aerospace, it's an engineering/business problem at this point.
[1]https://www.cnbc.com/2017/05/04/spacex-internet-satellites-e... [2]https://medium.com/iot-5g-extreme-ideas-lab/googles-balloon-...
You are also not going to be deploying your own balloon Internet.
2. Satellites can, in theory, run a mesh network among themselves.
3. Decentralized doesn't mean you own one. Decentralized means there are multiple agents and none have a commanding control of the system. I don't need to be able to deploy my own internet balloon to belong to a decentralized system. Cheap internet balloons will allow smaller companies to work on the "last mile" problem, further decentralizing the network.
4. Decentralized doesn't mean free as in beer, free from commercial interests, or free from laws and regulations.
Demand is also limited. Not a great combination, so your vision on multiple low cost satellite service providers isn't likely to come true.
There are only a few satellite owners you can buy broadband service from, not a 100. It's capital intensive and past bankruptcies don't bode well for new entrants.
Satellites can and do run satellite to satellite comms, a "mesh" if you like, but it increases latency.
Neither are balloons likely to be a viable long term solution.