Comment by kakwa_

Running your own git server is far from impossible. But you have to take into account various items.

1) the cost of the server, you don't need a powerful one, a 5 or 10$ a month box is more than enough, but it constitute a barrier for some, not necessarily because they can't afford it, but because they don't think their projects is worth it.

2) You have to maintain it properly, applying security fixes, having backups and maybe some basic monitoring. It's not high and complex maintenance, but it's far from a fire and forget thing.

3) Contribution from external sources becomes harder, you generally don't have basic "fork" and PR buttons in the simpler hosting git options, and if you opt for something like gitlab or gogs, external contributors as to register in your instance.

4) Github is really convenient if you are searching for open source tools that does a specific task in a specific language. Having various self hosted git servers makes it harder to discover new tools.

I do run my own Gogs instance which mirrors my github repositories, it's not heavy maintenance, but it's not exactly nothing. And I'm pretty sure nobody, except bots, knows it exists.