Imagine in 8 years ago someone said "And so Mozilla has to compete with IE6 which will eventually make Firefox better and in the end the web wins". Just because there is another browser that is significant competition doesn't necessarily mean good things. It's especially true if any one browser becomes too dominant, then all the other browsers have to conform to that browsers decisions.
I'm not saying that Chrome is going to become the IE6 of 2015, but if there is ever a point where Chrome can either do what is best for the web/user or be better for Google's bottom line they will always be choosing the latter.
Look at the state of flashblock and adblock in Chrome. It may have changed, but when I last looked at them they were both complete crap compared to their firefox equivalents. Google has very little incentive to improve their plugin system to make them more effective, but that would be counterproductive to what they are trying to achieve. I wouldn't be at all surprised if there comes a point when they are trying to push alternate formats for streaming video over Flash and it will suddenly become very easy to block Flash effectively and efficiently in Chrome.
I use Chrome and I like it, but I generally trust Mozilla to push for the best things on the web than any for-profit company, even Google.
"And so Mozilla has to compete with IE6 which will eventually make Firefox better and in the end the web wins"
That is exactly what happened. That's how Firefox was born if you remember. IE6 was dominant and Firefox rose from Netscape's ashes to challenge it and it turned out to be a very good thing.
Indeed and has lead to much greater cross browser support for standards, it ain't perfect but it's a lot better now. Even IE7 was a breath of fresh air and that was practically forced by the competition from FF, Op and the like.
I mean, if you follow the money trail, it's just as important to Mozilla that Google does given that's where a large chunk of their funding comes from.
