Complexity & Security
IPv4 is generally the first exposure people get to networking, when you see addresses like 192.168.0.1 and 127.0.0.1 these are IPv4 which is what we were using decades ago when Internet rolled out to many areas. This system worked, but is a little limited particularly in number of addresses. IPv6 theoretically replaces IPv4 with a more practical Internet architecture, key word being theoretically.
IPv6 has some slight security improvements, such as apparently making it easier to create internet connections through secure channels, but these improvements don’t seem to result in any meaningful difference for common configurations (and can probably be done with IPv4 or only small extensions anyway).
The showstopping problem with IPv6, however, is that you still need IPv4 to do anything in practice anyway. So with IPv4 you have a simple but limited internet style architecture, with IPv6 you have a new Internet but still effectively piggybacking off the old one.
If you’re just looking at features, this doesn’t really matter. IPv4+IPv6 gives you full featured internet architecture. But if you’re looking at security, maintenance costs, training costs … IPv4 is the clear winner, because IPv6 can’t compete with it without being twice as complicated in practice (still needing IPv4 configuration too).
Addressing
As for IPv4’s address space problem, this isn’t really an actual problem. 4 billion addresses is a lot! Certainly enough to coordinate more complex international communications and connect a bunch of smaller networks together. The problem is that the Americans basically saturated their IPv4 address space and the rest of the world kept using the same one, when we obviously should’ve done our own addressing prioritising our own servers!
So the problem with IPv4 didn’t really exist in practice for most of us, we were just limited by the American network not by the network protocol it used. Overall, IPv4 is basically fine and the solution to the biggest problem people said it has is just to deploy your own networks instead of relying on America’s!
It also seems extremely dubious to claim that IPv6’s addressing system actually solves this problem, as the addressing system is confusing enough for developers & administrators for everyone to know typical users won’t want to care about it.
Does IPv6 Solve Any Problems?
It obviously adds problems, but it doesn’t seem to really enable anything we couldn’t do before. It doesn’t seem to resolve the issue of IP addresses not really making sense on modern (mobile heavy) networks, it doesn’t allow me to connect to many devices that IPv4 won’t. So the tradeoff is not very tempting.
Is The IPv6 Internet Worth Accessing?
What has improved on the Internet since the introduction of IPv6? It may be designed to streamline access to social media sites with billions of users, but who likes these? Is it responsible to encourage this kind of usage of the internet? Shouldn’t different countries be running our own smaller sites anyway, and linking these, instead of relying on such a massive scale of connectivity for everyday communications?
Who Owns The Internet? Who Is The Police?
The standards authorities? The governments? The cloud providers?
Do those people represent my interests, my client’s interests, my community’s interests? Have those authorities really explained their own interests to the public in full?
No, I think this is our internet, and I am the Internet police. I think if we (average tech users, small businesses) don’t assert more dominance it will be taken away. So I control the Internet as far as it applies to my own business products, not them.
Summary
Obviously I’m biased, I’ve already ported an IPv4 stack to my OS and am too lazy to implement IPv6, but I think a lot of people are starting to have similar thoughts about whether IPv6 was maybe just pushed to distract us from making our own infrastructure instead of solving any real problems. After all the idea of every person on the planet being able to connect freely (the excuse for needing so many IP addresses) will never be viable on an internet controlled by Western governments.