Heck, I'm thriving right now. My army is bigger than ever, and I've managed to find a full load of lvl 9s to support it. The trick?
It's all about location.
My alliance found a nice spot away from most of the players. I moved most of my cities there, leaving two behind in the pack. After a shaky few days, level 9 crops started showing up and refuse lifted. I gradually stacked oases as they appeared, training a dedicated cav force for capturing/refreshing them. I farmed inactives from my two bases in the main pack. (There are actually quite a lot of mid-level inactives, with a high enough crop output to refill a full warehouse every few days). One of the biggest changes has been the lack of forts to farm. Virtually all the high-level forts are occupied, and I don't think the level 1 two mins from me will do much good. Inactives are the new forts, so if you're not by a lot of them, find a good spot and make sure you have enough population to ship out the crops you need when you need them. An added benefit of this is you'll have some cities by a lot of people for quick prestige strikes.
If you want to flash raid forts and steal oases, by all means go right ahead, but just remember you're inviting the other guy (and his alliance) to do the same to you

. So if you take this route, a small guerrilla force would be the way to go (and could be immune to retaliatory cropping/farming). Provided you weren't being farmed round the clock, you could live quite well this way (though everyone would hate you).
Looking forward, there IS enough resources and crop to support everyone, you just have to find it. Work with your alliance to find forts and oases and train cav to get them quickly. My only concerns would be if a huge number of people suddenly tried to support gigantic armies, and those who are supporting them running over those who aren't.
In the case of the former (which is probably unlikely), the already entrenched people with humongous armies would be able to repluse most of the emerging super-builders, and for the remainder it would become a war of brains and strategy to eke even more crops out of the land. Those lacking both would crash and burn after a few days.
The latter would be something I am more worried about. This is a game, after all. And the point of a game is to have fun. There's no fun in being farmed and cropped by superbuilders or people whose ego could use some trimming.
All that being said, you want an army size you can support with the time you have to play. Don't tear yourself up and get really mad trying to support a huge army without enough time.