Speaking of crossover parts, it is easy to take an inexpensive low and mid grade speaker to a much higher level by just replacing the caps, resistors, and inductors to higher quality ones. I've done this to 4 sets of speakers over the years and have had wow reactions afterwards.
Speaker companies have relationships with capacitor manufacturers for their supply chain. For example a high end capacitor manufacturer such as Mundorf supplies all the caps for their entire line. The top product could use their oil/silver/gold caps that would cost a normal person like you and me $100 each but are sold to the speaker manufacturer for a little over cost at $20 each but the manufacturer also buys the cheapest Mundorf without any branding for their lower products in much larger volumes. These relationships are made over years and even decades.
Speaker companies have relationships with capacitor manufacturers for their supply chain. For example a high end capacitor manufacturer such as Mundorf supplies all the caps for their entire line. The top product could use their oil/silver/gold caps that would cost a normal person like you and me $100 each but are sold to the speaker manufacturer for a little over cost at $20 each but the manufacturer also buys the cheapest Mundorf without any branding for their lower products in much larger volumes. These relationships are made over years and even decades.