Ouch! I suppose you're the guy who came up with title?

For me, the issue was that I didn't know what a "Grothendieck" was and the title doesn't give you any clues either; in fact it explicitly denies that any exist.

It also flouts the convention for fanciful non-fiction titles, which is something like "Clever-or-poetic-part: plain description." Something like "A country of which nothing is known but the name: Grothendieck and mathematical motivation" would be better, I think.

Or maybe, just maybe, it could have been about some actual forgotten country where only name of a city or something survived?

Obviously you can use whatever title you want and be as poetic as you like, but at least in my mind I was going to a very different place than "mathematician".

As for your examples, they don't really fit, since we have way more context about them. If you are going to see a movie with a title "No country for old men", you can be pretty sure that the title wont be literal (unless it's an comedy movie, in which case it might be). As for the quote, most people get that "past" is past and not some place and certainly they are not going to start looking for "yesterday" like you suggest, that's just stupid of you to even suggest. Anyone who is aware that "yesterday" is part of "past" already knows what you are talking about. However most people do not know who or even what Grothendieck, to me it doesn't even seem like a name of a person, but that's just me.

EDIT: You can downvote me all you want, but unless you can come up with coherent response, please think twice why you are downvoting.

Perhaps people expect a title to be either helpful or artful. This one is both less than descriptive and uninteresting. People would probably be be less concerned that it wasn't descriptive if the title was artful or clever.

Yes. Actually.

That was why I clicked through also--I was expecting some sort of historical oddity!

Even if you know who Gronthendieck is, the title is surprisingly unhelpful.

When I read the title, I assume Grothendieck is a country. You know, because it says "Grothendieck is a country". So maybe you don't need to say "Grothendieck, the mathematician", but the title is specifically going out of its way to be as unclear as possible.

I literally couldn't tell you even what part of the field he was involved with or when.

Although I could tell you that Zuckerburg made Facebook.

Just because you know something doesn't mean it's common knowledge (or that other people will even care)

Being an influential mathematician doesn't really put you high on most people's awareness.

But you're misstating the problem. If the title had been "A country of which nothing is known but the name Obama", I would still have assumed that it was about a little-known historical nation that happened to share a name with the last US president. It's just a really weird, confusing title.