Most people don't actually want to maintain a fork. They would prefer that their patches are mainlined.
Consider Linux. It's huge and most vendors really don't want to maintain a fully independent fork. One reason they might do it anyway, is if they could keep their patches private. But the GPL means they can't, so most just choose to upstream patches.
> Most people don't actually want to maintain a fork. They would prefer that their patches are mainlined.
But that's a downstream decision regarding efficiency in their developing process.
That's not what free software is about, there is nothing about that in its principles nor licences.
That's just Development Process and maintenance decision, offloading patch integration to upstream, which they might or not accept depending on your changes. None of that is about Free Software. You can see similar decisions/trade-offs taking place in any org with multiple software dev teams with ownership over libs etc, regardless if it is free software or not.
Consider Linux. It's huge and most vendors really don't want to maintain a fully independent fork. One reason they might do it anyway, is if they could keep their patches private. But the GPL means they can't, so most just choose to upstream patches.