I use Google most of the time if I want to source information. No surprises there.
I guess it would be problematic for Google to highlight the search criteria when displaying the resultant pages, otherwise the company (and other search engine developers) would already have implemented such a feature.
Try using the Maxthon browser. Searches can be made in any or all of several search engines including the default Google and all the results are highlighted by default, eatch term in a different colour.
Not a bad browser either, lots of nice little tools with it.
The simple reason is that Google only provides links. When you click on one of the search results, you leave Google and end up in another web site. Google has no control over how that web site is displayed on your computer.
That is, unless Google has some way of telling your browser: “When you go to the next web site, highlight these words,” and your browser can understand such directions. Which is what Google Toolbar does.
Also, if you go to the cached page (i.e. click on “cached” in the Google result), Google displays a copy of the web page stored in Google’s archives. So it can, and does, highlight the search terms.