Final answer:
The primary motivation for the development of IPv6 is address space exhaustion.
Step-by-step explanation:
The primary motivation for the development of IPv6 is address space exhaustion. IPv4, the current version of the Internet Protocol, uses 32-bit addresses and can support approximately 4.3 billion unique addresses. However, with the increasing number of devices connected to the internet, this address space is rapidly being depleted. IPv6, on the other hand, uses 128-bit addresses, which allows for an almost limitless number of unique addresses, ensuring that the internet can continue to grow without running out of available addresses.