If anybody prevented war, it wasn't some last minute magic but rather slow and tedious effort years and decades before. Not something you get famous for.
It is also possible for war to be prevented by last minute magic deplomacy, albeit I would agree that it's the much less likely of the two options.
But it's also something that's much less likely to become public knowledge. Slow and tedious efforts over years and decades contains plenty of discussions of the sort that often can be made public to make both sides look good (or for each side to make themselves look good to their domestic audience), while last minute, last ditch deals to prevent a war that was about to happen is much more likely to involve deals/threats/whatever that one or both parties require remain classified for many decades.
