I don't directly deal with public peering, I leave that to my colleagues, my only practical BGP knowlege is on private ASes.

Your shitty ISP doesn't give you an ipv4 access, that's fine. ipv4 address blocks cost $20 an address and are cheaper today in real terms than in 2016, and have been coming down in nominal terms for years.

ipv6 makes sense at a global scale, it still makes no sense for many individuals with a good ISP, mainly because of how it was implemented, too much stuff still relies on ipv4. If you have to also run ipv4 then why run ipv6.

I have no services I use that are ipv6 only

I have services that are ipv4 only, so I have to run a 6:4 nat

I want a stateful firewall because it's not 1999

I want to handoff to multiple consumer ISPs, using PBR, not running BGP, so I need to use NAT66 (changing IPs isn't good enough, I want to round-robin based on various rules, send traffic to dropbox via one ISP, send udp via another, etc)

I have software which doesn't work on ipv6 on a client, so I have to run CLAT on the device

But not all my local devices can run CLAT, I thus have to run dual stack to use ipv6 successfully.

Thus as I'm running ipv4 anyway, and running NAT, there is no benefit over running ipv4 only. IPV6 adds more things to go wrong (NAT64/DNS64), but offers no benefits.

Even without the ipv6 client requirement I still need to run both NAT64 and NAT66. I have an ipv6 only network at home which I put phones on. It works, but there's no benefit other than keeping awareness of ipv6.

Now sure, the reason that ipv4 addresses are cheap is because other people are moving to ipv6 (especially mobile), and relying on 464 gateways, with 46 in their CPE and 64 on the ISP level. That's great.

But that doesn't change the equation for someone with a choice of ISPs, as they can choose an ISP which provides them with static ipv4 addresses.