Earlier quoted context omitted.
True, but then Google doesn't just download the page source and index that. They run JavaScript in some cases to get to the actual content. This must come at a significant cost. Their index is enormous as well: "The Google Search index contains hundreds of billions of web pages and is well over 100,000,000 gigabytes in size." https://www.google.com/intl/en_uk/search/howsearchworks/how-... Doesn't mean you have to be…
Sure, download and run the javascript, but then you can snapshot the DOM, grab the text, and discard all the rest. The HTML and js is of little practical value for the index after that point. Google's index is likely very large because they don't have any real economic incentives to keeping it small.
Yes, absolutely, I didn't mean to imply otherwise. But first you have to figure out what you can discard beyond the HTML tags themselves to avoid indexing all the garbage that is on each and every page.
When I tried to do this I came to the conclusion that I needed to actually render the page to find out where on the page a particular piece of text was, what font size it had, if it was even visible, etc. And then there's JavaScript of course.
So what I'm saying is that storing a couple of kilobytes is probably not the most costly part of indexing a page.