Why can't search engines customize sorting?

Why do you think of this problem, I do not know. Sorting is a very useful feature, Excel,erp soft drawing has this function and is used every day. Why does the search engine not have this function?

The first possibility, not yet thought (almost impulsive to comment). Think about it impossible, Internet development more than 10 years of such a small function did not think.

The second possibility is that the technology is difficult to achieve. I do not analyze this, I hope to study the search engine students to publish their views.

The third possibility is that the current function is sufficient. If this is so, than the first case is also terrible, not worry about later no search, but really did not then ...

The fourth possibility, copy the homework when the other people's name also copied over. It's not possible to think with your butt.

The fifth possibility affects advertising revenue. The intention is to write a "Please marketing students to express their views" on the end of this analysis, but think about the technical community where there will be marketing classmates, or I come to analyze it indiscriminately. Search engines rely on the ads in front of the search results to make money, in order to allow customers to dig more money, hot keywords and the location of the top of the cost is higher, if allow users to sort by themselves may affect revenue.

Joys six kinds of possibilities, the industry is not competitive enough. When the first search engine allows users to sort freely, it will marginalize the old search engine such as Google and create a new ecosystem.

Why can't search engines customize sorting?