A very good player once told me that the beginning of a world is a sprint (at least in the core) which allows for a relatively small group of players to quickly dominate, but once the top 30-50 players quit the world is there for any alliance's taking. Having played several speed 2 revolt worlds out, I've seen this come true each time.
Why do top players quit after only a few months?
Because right now players either gain their dominant position though ridiculous activity or they purchase their way to dominance. Neither of these things scale well in the long run (gets too expensive, or life catches up with those players). Some top players quit because they feel concerned about addiction to the game or they burn out. Of course there are exceptions but I would not expect more than 10-15% of the top 30 or so players to still be on the server or in that ranking in 4 months.
It's true that Venom 2.0 leads in every statistical ranking right now, but how long will they keep this up? Remember that even the best alliances can only produce culture so fast... which means that even unrivaled, Venom can only expand so fast and definitely won't "kill the world" unless they manage to destroy the very organizational structure of the alliances that oppose them. Moreover, Venom 2.0 players have a great track record but that doesn't tells us if they can invest a long term effort into the server. Grepolis is only half about what you know - and the other half is about having time to invest in the game.
I agree that a lot of players are there to rise to the challenge of a good alliance. I hope that Inno doesn't release too many new worlds in the next few months because that is really what will kill this world. In o45 it may seem like Venom 2.0 is overpowering you - and I'm sure they are - but out here on the rim they just look like another elite alliance that will drive diplomacy around them and vanish in a puff of smoke a few months down the road.