I'm not sure, but it almost seems like marvel is trying to write maximum security our of existence. Issues presented in it like the Ruul, ego trapped in quasars bands, the alien colony in the swamps of georgia, humans prophesized as a threat to life in space, etc. seems forgotten. It's almost as if when busiek left the avengers all his plans were written out of reality.
That's not limited to Busiek. These days everytime a writer leaves a book, the next writer tends to ignore everything and start with a blank slate.
As far as Ego goes, I imagine the Ego spore was released when Quasar died and Ego was reconstituted, as per his appearances in Nova.