Google is a search monopoly in some locales, but what I wrote is more about their acting like a browser monopoly.
In a more balanced market, the "defect" choice in the Prisoner's Dilemma is to crank out proprietary stuff and leave your fellow prisoners twisting on the reverse-engineering treadmill (update: don't try open-washing me: NaCl being licensed freely is meaningless when Google controls this very complex pile of code that depends on a deep/wide Pepper API into only one browser; Dart may be simpler but open-source != open or "free"; some vendors such as Opera cannot use any open source).
The "cooperate" choice is to bring prototypes and proposals to standards bodies and gain buy-in and interop.
Yeah, Netscape did a bunch of stuff without standardizing it with w3c or any other body, definitely including JS. We made Microsoft reverse engineer JS as JScript (poor them!). We took JS to ECMA in the second year and only under some pressure from MS and non-sock-puppet web devs. Nothing I can brag about there. That was then, and everyone paid a price.
Now, are you suggesting that Google is the better Netscape, the "good" monopoly? I don't think so.
Again, I'm not moralizing. I'm not the dry drunk lecturing the kids to avoid having the "fun" I had. Google will do what it thinks best. My objection is that we have a non-monopoly browser market, not even a duopoly, with pretty good open-standards innovation. Dart goes the other way and puts the open web at risk. It is fragmenting.
On JS evolution in Ecma TC39, no one wants design by committee. I spoke about how we strive to avoid that in TC39 at TXJS. Give my blogged video a listen if you can.