I don’t believe there is any such thing as Inbox Zero.
I think it’s one of those Holy Grail type of scenarios - we all keep searching for it, but we will never find it, because, in all probability, it doesn’t actually exist. Just like there’s no Ark of Covenant, no Loch Ness Monster, and no better football team than the 2003-2004 Arsenal Invincibles. (Yes, I said it.)
But while it may not be practically possible to get to Inbox Zero, that doesn’t mean we should pursue it.