Passive bi-amping in my opinion gets you nothing. The amps do not have to deliver current outside of the band where they are being used, but I don't see this as any huge benefit, worth the expense.

Options for audiophiles to make "tweaks" to their systems have become almost nil in the last decade or so, as more and more components have become "black boxes" that contain no components that can be changed out by the consumer. Consumers have to resort to "tweaks" such as passive bi-amping, cable swapping, designer AC cords and other things which do not really make fundamental changes like were possible when you could actually work on the components' insides. DIY is not nearly as popular as in the past, with the passing of most of the companies which produced excellent "kit" components such as Heathkit, Eico etc. A small number of kits are available, but they are not in the mainstream where the masses are likely to find them. Hi-Fi used to be a fun hobby for more people because of the more intimate relationship with the components, which were built by the users. Too bad......