We, as people who build the internet and want to see it prosper.
I think the web will continue to be the dominant application for some time, but there are other competing proprietary systems like iOS that could replace it if the web stagnates. No, Google shouldn't have that power alone, it should be a free market where any browser that does what people need from it can be used.
Without IE8 web applications will be less dependent on libraries to fill the gap, cheaper to build and higher quality.
These companies need to change as well.
These people need schooling.
They care about the web and are moving it forward. If people change from IE8 to Firefox, Chrome, Safari, Opera or IE9/10 they will benefit.