There's a reason nobody had yet grasped it - it's not easy. Sure, programming in HTML isn't exactly rocket surgery, but building an OS to support solely those apps is a more difficult proposition. It took webOS a while to get its footing, too long, in fact.
Today the dream has been revised. webOS is still at its core based on web technologies, but the dream is of those web-coded apps being everywhere and breeding success back down to the to-be-open-sourced webOS. Today's open sourcing of the Enyo application framework was the first of many steps to fulfilling that dream, and it's a pretty big one. It didn't take long after the announcement for Enyo-based apps to find their way into our browsers and other platforms, and we imagine that's just going to be the beginning. There are plenty of well-built Enyo apps that we're certain developers will be excited to be able to bring to other platforms without much effort (at least compared to the effort of completely rewriting the app for other platforms).
Today was really all about Enyo. Having the roadmap for the webOS open source release is great and all, but it's just to set expectations. We now know what we can look forward to in the coming months (ha, gotcha!), but at least in our estimation the most interesting item on the list was the very last one in September 2012: Open webOS 1.0.
The revised dream is that by making webOS a new alternative to Android they might be able to pick up some marketshare in the process, making it easier to justify bringing back webOS hardware from HP. That's part of why HP's reseting the version counter to 1.0, and maybe pulling off a rename here to Open webOS (though personally we're still likely to just call it webOS if that's the case).
That's the dream. Now if that will be the reality, that remains to be seen. But at least today's news not only puts us a step closer, but also makes it an actual possibility. An open source application framework is one step, but we have to hope that Open webOS 1.0 takes massive leaps ahead, because that's exactly what the competition is going to be doing too