The reason why the 568B order is used is because of the signalling requirements of various layer 1 networking protocols that travel over these cables.

For instance, twisted-pair ethernet uses pairs 1/2 and 3/6 for transmission and reception, so making sure that 1/2 is one twisted pair and 3/6 is another, you reduce crosstalk in the cable.

Some telco protocols like ISDN use pins 4 and 5 in the cable; this is why 4/5 is a twisted pair in EIA/TIA-568B. The goal is to make an EIA/TIA568B patch cable usable for as many different communications standards as possible, providing twisted pair paths for all signalling as often as possible.