Dries' "State of Drupal" keynote at Drupalcon Prague is already available, and it's worth listening to in its entirety:
There have already been some excellent summary notes written about the keynote. Alongside those, I think it's worth transcribing what Dries said about the recent Backdrop fork: he starts talking about it at around 59m40s and I've very slightly paraphrased what he says below.
A couple of things I want to say, and I want to be careful about the way I say them as well. Obviously forks are a fundamental part of open source - it's a right and a freedom to fork. A lot of forks are great, in the sense that they allow and encourage collaboration: Pressflow is a great example. But all forks are collaborative in nature, and that's fine too. Sometimes there are philosophical differences, and sometimes it's the best solution to split the community, or to fork the community.
I don't like that, and I think what we should to is we should continue to listen and talk, and figure out what we can learn. So, you know: reach out to Backdrop, and see if there's ways we can pull them back in. I haven't spoken up about it yet, because I think it is a kind of a process: it takes conversations and it takes time to work out what exactly is going on. Usually it starts very emotional, and over time, like with many things in life I guess, emotions start to disappear and there's more room for rational thinking. So that's why I've basically decided to sit back and wait a little bit.
But I'm not afraid of the conversation, and I hope that we can bring them back into our community. If that's not the case, then at the end of the day that's fine too; it may actually be better: instead of having a disagreement. If that's the case then the only thing I can hope for is that that breakup is honourable, and we don't start fighting and that kind of stuff.
But there's a lot of things going on, and I think we're already committed to a lot of things, like the switch to Github[....] As the Drupal Association, we're studying right now about what might be best[....] Our packaging tools do a lot of things! So how do we get that in a Git[hub] world? The issue queues[...] aren't optimized for what we do[....] We're committed to improving the developer experience.
At the end of the day, I also believe we need to move forward. The web is changing rapidly, and I don't want Drupal to be in a position where we can't compete. It's always a difficult balance between how hard you want to push - you need to push hard enough, to keep up with the pace of innovation - but if you push too hard sometimes that's not a good thing. It's difficult, but I think we'll get through it and things will be fine.
The last thing I want to say on that topic is that I feel very confident about Drupal 8. I really believe that it's going to be a great release. Which is not to say we can't learn things from others.
As always, I feel there are others better placed to critique some of what he says; I think there's a clear message here, which is that forks, and any possible future merges of them, are a long-term process. The Drupal/Backdrop community needs time, space, and thoughtfulness.