Active biamping is also usually a big mistake. Unlike mere "buy-amping" (using multiple amps on a speaker all feeding through its passive crossover), active biamping can actually be sonically deleterious, rather than just a silly waste of money and energy.
The only exception to the to that rule is when the following two conditions are met:
(1) the crossover unit has significant EQ capabilities (many do, e.g. miniDSP, Behringer DCX2496, Ashly Protea, etc.; older analog units generally are useless, unless used with a high-quality parametric EQ in a separate box) AND
(2) the user can take high-resolution polar measurements to make proper use of the onboard EQ.
I agree, that using an off the shelf crossover is not better than choosing an off the shelf passive one, and will be as disastrous.
However if you know what you are doing, active crossovers are easily modified to get the crossover points and slopes you desire. You have to understand how to modify the loop gains of opamps, and that is not rocket science.
Biamping has huge advantages, especially in the lower crossover points.
My system could never be what it is without active crossovers at selected points in the system.
In three way systems in particular, the passive crossover is a huge roadblock to optimal performance.
This will change. Now we have digital microphones, and the AES 42 standards to keep cabling optical, the push to keep everything digital from microphone to the final drivers will be unstoppable. So I think we will see, total digital pathways, to loudspeakers with digital DSP crossovers, and conversion to analog right at the class D amps for each pass band.
The car engineers know it, and there are already there. That is the way my car audio works, and the sound is amazing.
This will come to homes near you much sooner than you think.
