A home, social, or (especially) work situation where there are a number of people around you with huge egos, all trying to out-do each other. Also refers to the 'pecking order' within these groups.
"Hey Bill, how's the new job going?"
"Not bad, but they're all pretty much egotistical wankers, so I have to spend my day living within a finely-balanced and delicate egosystem."
n. A system of delusions that supports a person's overinflated sense of self-worth and importance. Egosystems are bizarrely robust despite often being overextended and lacking the actual elements that would otherwise legitimize it's sustained existence. Woe to the realist that points out the delusions underpinning an egosystem and potentially (but not likely if you're dealing with a real douchebag that won't believe you anyway) precipitating egosystem collapse... for shame!
Kanye West's behaviour isn't symptomatic of off-the-charts arrogance, but rather it's a manifestations of his extensive egosystem which simply consumes everything in it's immediate environment.