Pretty true indeed, when doing my researches I did find some VSTs by OrchestralTools (Babel and Eternal Vocals mostly) that seemed pretty alright for the price invested, also considering that they make very nice free orchestral VSTs : I'm just not sure if they are flexible enough for different musical styles (the demos sure do sound pretty nice, but what are they like in my DAW ? That's a mystery).
Also yeah collaboration with other talented people would surely be the best way to go for higher pitched vocals (I did do the other vocals on the first track but I do have my limitations), maybe I should check this at some point.