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.