Yes, I understand all of this. It can work for small websites. However, the technique cannot uphold for larger systems. For example, consider writing a word-processor using this style of programming. If the user is writing a 10-chapter book, and every character entered by the user requires a visit of all characters in the book, that is not very usable. So even from a practical viewpoint (not just theoretical) it is not workable.

Also, consider adding items in a streaming fashion (one-by-one). If there are N items to be added, then the amount of items visited by this scheme is 1+2+3+...+N, which amounts to O(N^2). This is quite ridiculous.

Also don't forget about power consumption, which is of course very important for mobile applications.

Finally, The solution is not satisfactory from an intellectual viewpoint. Instead of trying to be smart, we are lazy, and abuse abstractions to make our lives easier, and at the same time our software behave slower (especially now that progress in speedwise performance in hardware seems to have stopped).