I was just thinking the same thing - Google is in many ways an engine of innovation, and they bring a lot of cash to bear on a problem. But as you suggest, the same was true of Microsoft in the late 80s and early 90s. The only real difference is attitude, and attitudes change.
As someone who makes use of Google's services, I think this is great, but I can't help but wonder whether this is ultimately stifling advancement in the field. Google doesn't NEED to innovate in voice, it just WANTS to. In some ways, that results in a better product: they take risks a small software house dares not. But they're not as committed to innovating, and they drive a lot of people out of the market. Gmail is a great service, and Google continues to do new and interesting things. But I haven't seen a single new webmail service since Gmail went live, and that's a little worrisome.
As a software developer, I used to worry that Microsoft might find my particular niche potentially profitable. Now I worry that Google might think it's cool.