Second thoughts...

Of course in a perfect world, there would be pre-amps capable of assignable multiple outs that are configurable by the user to facilitate bi-amping. Not sure what the engineering impact would be, but if designers can fit two Zones in a single pre, it can't be impossible.
Other applications may be for front/rears centers or multiple subs assignable by the specific layout of the user. Pipe dream? Maybe. Future proof? Possibly. Practicle? Probably not, but I hope so.