I'm still going with "numbers are all off". I've actually had quite a bit of combat in my current game despite the "vanity" thing, and I have.... 65 points on turn 20. Without the vanity it'd likely be more like 120-ish, based on how many units have been produced.
The funny thing is, you're describing very well why a survival victory condition is completely broken. You have to go really out of your way just to get stuff destroyed. Notice in my save game how everything is nuts and complete destruction of a faction is not even close to happening.
Hm, it seems like individual units and buildings actually fall pretty easily.... but as the game goes on, the sheer numbers of each keep going up. The more buildings there are, the harder it is to destroy the other guys completely... but the more UNITS there are, the more of a crowded mess the map gets, and the less building destruction is possible.
Overall then, I do agree with you on that one; it's part of the reason why I love the score gate idea so much. I get that the idea of the game is that if one side gets too strong, they'll start snowballing over the other side, eventually leading to destruction, but this is actually a pretty slow process and so far, not too hard to stop. It's actually pretty easy to bolster the unit count of a given side, as military buildings (and heck, new cities entirely) are pretty easy to make. You can also use mythological units of course, but not really in big numbers.... it's easy to get big numbers of human units to add to a side though. And of course it's not JUST these.... you've got things like the big god powers that can fix things fast. Heimdall's "kill everything" horn for instance can do this.
EDIT: And there's also bandits! Logically bandits should add to the danger, but I find that they tend to instead add to the DISTRACTION: Units fighting bandits are NOT attacking the other side and thus not throwing off the balance at all.
I have to wonder if a different condition other than the "total destruction" one is necessary (and the score gate would be left in place). Because you're right, it seems like it just doesnt quite work that way. Not from my experience so far anyway. I dont have any suggestions on what such a condition might be though.
The score one though is the one that interests me the most anyway.