How feasible is it for a non-distributed web crawler running on consumer hardware to search the internet?
This is not remotely feasible. The number of pages indexed by Google and Bing are in the tens of billions. To get anything close to what they are doing you are going to need to process terabytes of data. It will take you days to download all of these webpages using your home internet connection at full speed. And you will probably hit some bandwidth cap by your ISP before you finish. Even if there was no bandwidth cap from your ISP you would have to be careful in how you request the pages. If you request too many from one server in too short a time you'll probably get your ip blocked by that server. So you'll need some kind of program to optimize the order in which you visit these hundreds of millions of URLs. You will never be able to finish visiting all of the URLs in your queue. New content will be added to the internet faster than you can keep up with it.