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.
Where things went off the rails was the things Microsoft refused to implement due to their monopoly position. They had a binary component architecture, but it wasn't sufficient to run Java. They had Java, but it was a vestigial and crippled version. Their HTML/CSS engine was just "odd", incompatible not only with emerging standards but with any published standard at all.
Basically "the problem" with IE wasn't that Microsoft "did whatever it wants", it was that it did (or didn't do) very specific things intended to prevent users from wanting to use IE at all, in a vain attempt to favor desktop applications or IE-specific implementations.