I think the biggest way this is escalating is the telling "download google's new browser" link that tellingly found it's way onto the (famously traditionally sparse) google homepage.

For many non-tech-savvy people, Google is the internet. Just like people type URLs into the google search box, if they see a message saying "download new browser from Google" they're likely to interpret it as "download the new internet"..!

Fair to say that never before have so many "mainstream"/consumer computer users been exposed to such a simple call to switch browser..?

I've been thinking about that a bit. The fact that Chrome needs to 'sell' to users that haven't even made a switch from IE6.

But is that really the case?

Maybe the issue is 'will it be compelling for developers?' (Maybe this's more of a question for gears). But Salesaforce.com is a good example. What if you told users that they need to download a new browser to use an app. Still probably easier then downloading & installing a piece of desktop software (and it's by google).

If a modern browser really enabled things that are just impossible to do in IE6 (or a browser without chrome), developers would develop for them and that would push user adoption.

IE6 is annoying, annoying pushes user abandonment. But it's not enough to push developer abandonment. For that, you need 'prohibitive'.

I think the day developers are making a choice between developing for certain browser(s) or developing for desktop, is the day we have a compelling reason to switch.