Sure there is, because this game had *plenty* of theoretical progress. Half the draw participants could have been cut out! The game was *not* diplomatically stalemated by any means and could easily have been reduced to a 2-way draw, so there was ample theoretical progress and thus certain basis to continue the game.
If, say, Russia were holding Warsaw, Moscow and St. Petersburg, and ordering War+Mos S Ukr (presume France is dead, Germany got Marseilles and is holding it, Italy has Sevastopol for 17), that would be another matter; Germany could not safely eliminate Russia, and so the coalition is diplomatically and tactically stalemated. At that point continued holding out would, indeed, be ridiculous.
The way I see it, there are three options for such a scenario:
Pro-Leader: Force the coalition to kill every nonessential member and force the leader not to advance in order to minimize the draw. This unjustly removes the right of the coalition to keep valued-but-nonessential members of the draw alive, and so should be disregarded.
Pro-Coalition: Force the draw once it becomes clear that the coalition does not wish to kill any valued-but-nonessential members. This unjustly removes the right of the leader to fight diplomatically for a reduced draw, and so should also be disregarded.
Neutral: There should be no intervention and the game should continue until one side caves. This is the fair view, in my opinion, as it does not infringe on the rights of the coalition or the leader, and does not call upon moderator intervention. The ensuing battle of wills would reflect part of the spirit of the game: you are all diplomats, and if you believe your current foreign policy objectives are just, you should fight for them, not call upon the equivalent of God to resolve things in your favor.
Some might say this violates the "keep it fun" rule; I say that's not necessarily the case, as especially in press games the tense endgame negotiations that would result could certainly be very invigorating and enjoyable. Whether something is "fun" is entirely up to the players; I almost question why this is even a rule, because all it seems to do is justify moderator intervention to make the game fun for one side at the expense of the other side, but in any case, these scenarios are not always "not fun," and to argue they always are is nothing more than personal projection onto other players, which is a terrible way to craft policy on any issue.
I'm sure some would also argue that it violates the "Use common sense" rule. Frankly, I've never understood why we have a rule that appeals to the most egregious of bullshit pop culture truisms in existence, as "common sense" is nothing more than a useless buzz word employed as a laughably fallacious appeal to popular opinion as an authority, and again it strikes me as giving moderators undue freedom to influence games as they believe is right, without taking into account the will of all the players involved.