TL;DR bigger fishes to fry ATM - yes you need IPv6 to scale, no you don't need it right now.
When the ipv6 spec was released, the latest python release did not yet support list comprehensions.
In other words, there is no reason to not support ipv6 out of the box in 2022.
i'd go even further and say that no ipv6 support means obsolescence.
Use the age of a service as the metric, not the absolute year we're in. It's probably reasonable to say that there is little reason not to support IPv6 for an ISP with X years of operation. Starlink is young still.
An analogy is worldwide sales for a new laptop company. You can say that in the age of globalism, there is no reason not to ship to every continent right off the bat. But for a startup with limited cash that has lot of building blocks to lay out, it's a huge risk. They should plan for it, but only branch out when they've got a solid foundation.
"Our staff is more familiar with XP. We promise we're still working on the Windows 10 drivers, but in the meantime you can try to run it in VMWare."
Yes we do. IPv4 exhaustion is a thing.