Microsoft just did whatever they wanted with the web "platform", and so will Google.
In Microsoft's case what they wanted was nothing. They weren't a web business, saw it as a threat to their platform leverage, and so just left it abandoned and stagnant for years.
Google is simultaneously better and worse: they won't leave it stagnant because the web is their platform, but on the other hand they have a lot more to gain by abusing control of it.
It's perfectly possible for Google to be engaging in similar behavior to Microsoft during IE era, while websites decide to support more than one browser for the moment. In the long run, Google's behavior could contribute to more websites deciding to support fewer browsers.
I'm already seeing the occasional website that doesn't work properly on Firefox - for the moment this is rare, but I wouldn't be surprised if it becomes more common.