FWIW, I've been doing the web app tech schtick since about 2010 and since about 2011, I've been pretty consistent on the 2014-2017 time frame.
Everything is in a half-baked state because people start on a project, realize that other parts aren't good enough, so because they have work to get done, the move on to the tech that works for the job at hand. Things are finally getting to the point where web app tech has achieved "fitness for use" (the most accurate definition of quality I can think of), which means that library authors are no longer in a position where they have to maintain and grow a library in isolation while they wait for other libraries to catch up.
On top of all that, what has also caught up is the money. There is now real solid VC money backing up companies that either create webapp tech or are betting on webapp tech as part of their strategy. With money, you have people who no longer need to depend on the goodwill of others to push things forward.
Lastly, there's been a cambrian explosion in the general sophistication and knowledge level in the JavaScript community. NodeJS created a viable JavaScript environment free of all the bullshit that comes with myriad user agents. They made it possible for engineers coming from many other language communities (C/C++, Java, Python, Ruby, Perl, etc.) to really dig into the language and bring diversity of ideas and experience into the JavaScript community. That diversity is now jumping the network gap and becoming more common on the browser side of things.
Does web app tech meet the conditions of "fitness for use" for all use cases of native? Certainly not. There are several areas where, as you correctly pointed out, it's falling behind. But this likely won't be the case in about 2017, when the only remaining difference between native and web is going to be a performance gap of at most 2x for certain uses. There are not a ton of use cases where a 2x performance difference makes the difference between something being fit for use or not, especially when you consider other benefits native can't achieve like distribution via hyperlink and incremental loading of non-content parts with use.
One of the most important questions an engineer needs to ask is "Does it matter for my career whether I'm on the right side of technology when a fundamental shift happens?". For career engineers working in areas where native is likely to have an edge for years to come, it probably doesn't matter. But what happens if you're an engineer with an entrepreneurial bent like many on HN? Starting in 2008 and going into 2011, if you didn't have legit talent on your team for building iOS and Android apps, that was a problem for your business. Starting in 2015 and going through to 2017, the same will happen with web app tech. If you want to be in the right place at the right time, this is the year to actually start learning, so that you're well positioned for the next three years and opportunities shift.
Fundamental changes happen. It's valuable to be able to time things to account for those changes.