I will contest the points.
1. Apparently HTML5/JS can't create the same gaming experience. I will contest this. Language is not relevant to gaming experience. Developers and what they can manage with the tools they have hand matter. I assure a good team can provide some fantastic gaming experience with HTML5/JS. Keep in mind that Unity was in the same situation in the very early days. No one used Unity for "serious" games until a few major releases came and developers really picked up the steam.
2. HTML5/JS are not browsers. They are languages. The complaint is the run time environments(RTE) of the language. This is valid. however if you abandon the idea of supporting different RTEs and instead focus on a single RTE(NodeWebkit, CocoonJS...) you will make life easier. If you MUST abide by the limitations of supporting many RTEs.
However keep in mind that this is the same problem across ALL video games. PC is not the same language as PS3, 360(close), Linux, Wii, GC, DS..... all of these different hardwares give the developers who seek cross distribution the same headache... actually in fact using the browser RTE is less of pain as it's shared language. Just use common denomination of browser RTE and your good to go.
Keep in mind that there were game programmers working with with only 256kb disc storage, 640kb ram, 16 colours(and i'm being generous). If people can make robust RPG's that founded companies like Sqaure, Enix... so on. Then I'm pretty sure that everybody here can overcome the hurdles of browser RTE with 2gb+ram, 256mb+gpu, 2terabyte hard drives, digital distribution.
so I contest all the points. These trials of 4 mighty groups aren't just in the browsers, they are in hardware, OS and even API's as well. If other developers can overcome this hurdle to provide excellent gaming experiences. I don't see how an already fantastic cross platform technology is the limiting factor. When in face of what other companies need to deal with. Is the only tiny bump for us in comparison.
Though i will agree with another point. There is nothing wrong playing devil's advocate. it's really important. The discussion of examning idea's is super important. Getting people to evaluate there stance is important. It brings more innovation and thought.