pg has a good article on doing things that don't scale[0] and showed how the AirBnB guys went and setup the first listings manually, but it's actually far more general than just kicking off the network effect. Moats are things that don't scale. Open Source software scales perfectly. Billion dollar companies are billion dollar companies because they can use Open Source software wrapped around some Moat-able structure. The more Open Source Software that exists, the bigger the garden.
When Google spends a billion dollars sending cars all around the world taking pictures, they are doing so in a way that the Open Source world can't centrally compete against, as they don't have the billions to get that done. This means that all Open Source mapping software will be missing a crucial feature that users rely on, and will therefore go unused. But meanwhile the libraries that those Open Source Software use, Google can freely use within their walled garden. On the other hand, Microsoft paid a great deal of money to researchers with Encarta and had this same exact structure and Wikipedia came in and disrupted them. It takes more time for the decentralized approach to come online, but as long as it's possible and the data is kept high quality Google Maps will slowly lose market share to OSM.
So eventually decentralized open source software will catch up and these billion dollar companies will go to 0, but in the interim period, and as innovation never truly ends so there is always a new horizon, we should consider creating a better incentive structure.
The big problem with capitalism today is that we care very deeply about prices. Prices is where supply and demand match, but we no longer have any supplies. We have costs of 0 and values that can differ between people. Price is merely a negotiation between the two, with Open Source Software declaring 0% of the value, and Billion Dollar companies declaring 90% of the value. Price has become a flawed metric. What society truly cares about is the surplus. What we need is a way to do a sort of Incentive Compability system[1](i.e. a Vickrey Auction) so that these Open Source Software can show the value that they produce. If they can show that their development costs were offset by their users values, they should be funded for it. Linux would certainly have a much higher value than Microsoft in this view, and would therefore be able to fund their own data collection systems, and would likely leave those open to the world so that everyone could reuse the Linux Street Map data for themselves.
[0]:http://paulgraham.com/ds.html
[1]:https://en.wikipedia.org/wiki/Incentive_compatibility