This trend in mobile web performance should put you at ease. Here's the story:
The iPhone 3, launched in 2008, has a V8 benchmark score (version 5) of 23. A year later, it was 49 on the iPhone 3gs, and a year after that, was 83 on the iPhone 4, and 101 on the iPad. in 2012, the score is 1569 on my iPhone 5. For reference, my 2006 Mac Pro on Chrome 24 scores 11896.
Now, some of that is hardware getting better, and some of it is Mobile Safari (Nitro in particular) improving. Whatever the case, it has been roughly doubling (and sometimes tripling) every year. The iPhone 5 is now only 7 times slower than what was the most powerful desktop in 2006.
If the trend keeps up, in 2015, Apple will ship an iPhone that meets or exceeds the browsing performance of my home desktop. I don't have much to complain about the performance of websites on my desktop (which is why I abstained from upgrading it, and also because Apple won't upgrade the Mac Pro :( )
At that point, Web performance will be "good enough" (not necessarily better than native of course), that I think the pressure to develop native apps will be diminished. Moreover, HTML5 will be better than too.
Comparing Octane performance, we have a similar doubling, with my Mac Pro only 6x better then an iPhone 5.
Whether it is Apple, Google, Mozilla, and Microsoft's browser teams, or Moore's law, the mobile web, I think, is poised to make a come back, and at that point, I think development will split. Those developers creating intensive games and digital content creation/manipulation apps will stick with native, just like on the Desktop PC today. But increasingly, many basic content consumption apps will move back to the web, where the reach and deployment story is strong.
Don't count the web out.