Does Firefox 3.5 portend the end of heavy plug-ins?

For years, the browser experience has been built atop various substantial plug-ins, such as Adobe's Flash, Microsoft's Silverlight, or Sun's Java.

But as I learn more about Firefox 3.5, I'm wondering if this is finally the release where the venerable plug-in architecture starts to fade, as developers are finally able to build complete browser-based applications using solely the native browser features.

Consider these Firefox 3.5 (and earlier) features as a package:

• WebWorkers
• Canvas tag
  
• XMLHttpRequest security
• Audio and Video tags
  
• The Storage API (SQLite)

I'm sure I've missed some features, but the point is that these features, as a package, address some large proportion of the reasons that developers had for developing "substantial" browser-side applications using a plug-in such as Flash/Silverlight/Java instead of in the base browser.

I think it's very exciting to see that Firefox 3.5 is now sufficiently capable that it's reasonable to consider building a serious complete application hosted directly in the base browser, without all the complexity of having to exit to an external plug-in.