It's not, but with a little more imagination you could certainly take the author's work to the next level. Inline CSS and images as blobs.

Then in practice the issue becomes a bloated file that isn't able to reuse internal components, at least not without introducing a layer of complexity such as a scripting language and browser APIs to go with it.

Perhaps if HTML had been designed with more component re-usability in mind, the landscape of the internet would look very different today. Then again, what sense would there be in having a single HTML file for a site like Wikipedia or Altavista? And imagining the web evolving without a scripting language would be naive.

Single file websites that could be served up on blob or network storage certainly appeal to me, especially today.