blissblogger said:
because they spend a whole lot of time developing their sound? in each case you cite i'm sure their production development is a matter of going through synth presets/samples/etc. until they find the rare few that haven't been caned already yet sound good, then eqing/compressing/processing everything until all the elements sound good together. so each time they make a tune they go back to their old well-honed bag of stuff and maybe put a few new things on it. it's economics and pragmatism in addition to the desire for theming and such discussed above; i don't think any of those producers use engineers for anything except maybe mastering.