The interaction of crossover components(mainly inductors) has always been there, its not something that came along later and then accounted for.

Its always been standard practice amongst EE's to account for and be aware of this. It wouldn't surprise me if the hifi industry claimed it was ground breaking to be aware of this and hence brought performance upto a new level by adhering to these basic tenants. However there's nothing audiophile about it and is just standard good practise much like not using a 6" bass driver for a sub would be.