I agree things are speeding up, but think it's largely because Microsoft is now realizing that they need to keep IE up to date and standards compliant. They still have 70%market share, and it's not shrinking fast, so the onus is entirely on them. IE7 is kind of a sucky browser but a step in the right direction in terms of compliance, and IE 8 will be much better.
70% might be true in some places, but it's changing a lot.
For example, Mibbit gets about 19% IE usage on the main client. On the widget as you'd expect that figure is higher - 30%.
The surprise is how well chrome is doing these days - usually beating Opera and Safari, and sometimes beating IE6.
I think most of the push is coming from firefox,chrome,safari and opera. People using the new wave of webapps aren't using IE, because it's ridiculously slow (Even GMail now deter the use of IE).
I'd say it is shrinking very fast in webapp early adopter circles, and that's a key area of growth for browsers. IE better up its game with IE8, or get left behind.
