I posted about this too back in April. It helped make my point that browser games are a dying niche market. And making C3 so reliant on Chrome is like targeting a niche market within a niche market. I don't understand the business logic in that. Good gimmick, bad idea, imo. If C3 allowed people to make games just as easily in C++, can you imagine how many people jump all over that? We wouldn't have to rely on third party wrappers and all the problems that come with that, but I digress. It is what it is.
That being said, I don't think HTML is going anywhere for a very, very long time. So I think it's safe to make games for HTML5, even though it's not a popular method of playing games. A lot of people will still have access to playing your games online, if they wanted. More people have computers, tablets, smart phones than any particular console. Trends show the market shrinking for browser games, but it can easily rise again too. Nothing is written in stone.
I do predict browsers going away though. Eventually, HTML5 will be integrated seamlessly into the operating systems. Everything is moving towards seamless connectivity, everything from children toys to automobiles. You can already get search results and information without even opening a browser. That's the future of the internet. The faster C3 becomes independent of Chrome, the better... or any browser for that matter.