There are two psychological key aspects that are in play when it comes to this matter.
- Users want to feel as they are in control
- Users (people) want the ability to choose
The I'm feeling lucky feature does not cater to either of these aspects.
It is true that the user and the SEO will agree on the most suiting search result on a majority of the time. However, the amount in clicks is in no way a reflection on the time spent focusing on the additional search results. As seen in this graph:
The users will click the top search result a majority of the time. But at the same time they will on average also review the second and perhaps the third search result as well. This goes back to the previously mentioned aspects. Users don't want to feel like they're missing out on what they're seeking.
They want to be in control, requesting a range of search result and skimming through them. They want to choose, after skimming through the search result even though they on a majority of the time will choose the SEO top result.