> There aren't laws to ensure that. Within specific jurisdictions, sure, but not globally.
Many trademarks are indeed more or less global.
> A lot of companies also don't trade under their full name. Apple, famously, wasn't founded as Apple but as Apple Computer, and was only able to rename after achieving a deal with Apple Records.
That's irrelevant - Apple Computers owns the Apple trademark (for certain industries).
> The lack of more namespaces also led to things like nissan.com being owned by Uzi Nissan (and now his family, I assume) rather than the car company.
It's not perfect and not guaranteed to be unique, yes. But people's names have many orders of magnitude more collisions.
> @.name as an email address.
No, you'd at best get `??@firstname.lastname.name` as your email address. Which, again, is irrelevant, as it's impossible to say which of the many thousands of Firstname Lastname people this might belong to.
> (The cultural aspect is irrelevant - it was not enforcing a specific order. If people wanted to register lastname.firstname.com, nothing would stop that)
I wasn't referring to a specific order, but to the cultural idea that people have 1 firstname and 1 lastname. In Spain, for example, people typically have 1 first name and 2 last names - but you couldn't get `a.b.c.name` as an address. Having a first name, a middle name, and a last name is also very common.
There are also cultures where people simply have one name, not first + last. For example, a person's full legal name in Tibet might just be "Woeser".