Re: "I don't always need to look up the address of a bit of kit I need to contact"
Obscurity is the issue, IPv4 is Ubiquitous, IPv6 is niche, why go to the effort of scanning IPv6 space when there's plenty of low hanging fruit available on the easy to use v4 space.
It's the same reason there used not to be malware for mac, but as it became more prevalent, there is more profit in it.
v6 is just the DIAMETER to v4s RADIUS, both the first two are better protocols, but the second two are in use, people don't like change, and several features have been backported to make them last longer.
IPv4 addresses aren't exhausted, just their allocation is. a good 90% of them just aren't seen on the internet.
TBF if the internet core was run on v6 with BGP and everyone used NAT and RFC1918 addresses internally, there is no need for the added complexity of v6 inside an organisation
the NHS internally uses the RFC 1918 class A space and it hasn't exhausted it yet.
with proper use of NAT and CIDR and a re-allocation of unused addresses, v4 can last for a long while yet.
IMHO when they designed v6 they went overboard on the address space, there are enough v6 addresses for every atom of every person on earth to have 7
Biting the hand that feeds IT
