I've had native v6 here at home since my ISP was one that I also ran
If that had been the case for me, I'd made sure to make v6 a priority too. I did work at the equivalent of JANET from 2000-2007, so did a lot of early v6 work, and drove that adaptation at later employers too, with varying degrees of success.
Today, it is not hard to do v6, not as it was 20 years ago, when VLSI was built with the assumption that an address would be 32 bits. (and even earlier, only subnetted on whole bytes.. But I don't think there was much hardware-assisted routing back then, those sins mostly were in assembler or C.)
And, having a globally unique identifier for every computer, regardless how "internal" it is, is a major deal. It is an enabler you simply don't want to be without once you've tasted it.
You've got to remember that when I was first doing this a peering or transit link wasn't going to be bigger than 100Mb/s (except in rare cases) so hardware accelerated routing wasn't really a problem. We used to run our peerings on 7206s with all our IPv4 peerings and the early/experimental IPv6 and native multicast peerings running on the same box. The only thing there that was a headache was ever increasing BGP table sizes.
The only issue we ever really ran into was the plethora of stuff that couldn't do IPv6 full stop. Finding IPv6 capable CPE for small sites was the problem, if the customer was rich enough for Cisco/Juniper type edge kit you were OK but if they wanted to pay less than, say, £1500 you struggled to find something. As it was, the majority of 'customers' for IPv6 were internal (e.g.
me) and the few paying customers who wanted IPv6 were treating it as an experiment/early experience so it wasn't really that much of a headache.
The fun really started once you got to the era of trying to do IPv6 over broadband. In theory, all the middle layer was on L2TP therefore, in theory, it was no problem because, in theory, L2TP allowed transparent transport of layer 2 traffic; in practice it was a big headache as a lot of unnecessary and unwarranted assumptions were made by people who architected that middle layer which caused a lot of unnecessary borkage.