Internet Protocol Version 6 was promised to be rolled out in the year 2012. It would have given us more IP addresses than we will ever need and much better IP facilities such as Mobile IP.
IP addresses are now like gold dust, Microsoft have reportedly bought up all the remaining ones that they can. There are a maximum of 2^32 IP addresses with our current IPv4 system as they are 32 bit or 4,294,967,296 of them. IPv6 on the other hand would give up 2^128 or 3.4 x 10^38, a very very big number.
Every person and every device could have its own IP address. Part of the reasoning in not introducing IPv6 is the overheads, see my post on MTU’s or Maximum Transmission Unit size.