A lot of commercial speaker manufacturers, and that includes some expensive consoles, use electrolytic capacitors in their passive crossovers. IMO, a passive crossover should be built without the use of electrolytic caps which change values with time, since the cost of polypropylene ones is very reasonable.
Also, for the passive crossovers, many commercial speaker manufacturers use steel core inductors, instead of air core coils which operate in a more linear fashion and don't saturate at high power levels. Of course, manufacturers want to maximize their profits and they cut on quality for some components which are hidden.