Have you used Microsoft Live Image Search recently?
Have you used the new Yahoo search (with the automatic assistance and relevancy engines)?
Let me tell you - they are by far superior products over the Google search experience.
Knowing that, how much times do you think I used them in the last month? The surprising (or not) answer is exactly zero.
The billion dollars question is of course - why not?
If you ever tried to do the same search in Google, Live and Yahoo you probably noticed that about 70% of the results are completely different (even for generic and popular search terms such as "music" and "hot movies"). This means that "my Internet" can be very different according to my choice of search engine.
And this is exactly why even if they have better products Microsoft and Yahoo simply does not have a chance against Google.
The notion that Google search results are superior is so strong for all of us (even if it is far from reality by now) that whenever we don't use Google we feel that there is a chance that we are missing something important. We feel that there is a good chance that we miss the sites we really want to find.