It is not perfect, far from it, and the reason why so many Americans have second names (After all, USA had to Georges Bush as president)

A free form "full name" text could be the solution, but then the problem is forcing a formatting on it so that one person always puts the same thing in this field. Should I include second names? Accents? Is that family name first or second? At least, with clearly labeled fields you are already able to tell Adam Smith from a Smith Adam.

Webshops usually are happy with name + current address but there are administrative domains where this is not acceptable.

There are also differences with how surname/given name ordering translates between languages. For example, a Chinese name like Xi Jinping has Xi as the surname and is rendered in that order in both Chinese and English. A Japanese name like Shinzo Abe is rendered in Japanese as Abe Shinzo with Abe as the surname.

> sites insist on collection first and last names separately, as opposed to just a "full name"

Because that's also a cultural bias from (some) western countries. And even then some countries that "insist" on First/Last name don't have Middle names.

You might also want to split First/Last names to display things like Mr. Smith

In practice (especially for government purposes), John Smith is not only John Smith, but John Smith born in Day-Month-Year, in City, etc.