Why not put crossover networks in accessible compartments?

Some speakers do have a separate compartment such as the Dali Epicon line. Great way to keep the parts out of  direct proximity of the bombastic cabinet. Nola and others use outboard crossovers which add wiring complexity, but totally removes the vibration sensitive parts from the cabinet.

Thank goodness the dismal science doesn't rule everyone.

I believe a lot of these manufacturers would not have the crossovers accessible on purpose to hide the cheap parts they are using. 

Living Voice is another company that uses outboard crossovers. Other benefits beyond vibration control include...

- More room for proper spacing of inductors.  Far too many speakers have them jammed together due to limited space and this negatively impacts the Sonics as they interact. 

- Some of the better parts are just plain huge like PIO caps and heavy gauge, air core inductors for bass drivers. They won’t fit in the cramped internal speaker cabs. 

Volti Audio is another.