It took many years before mobile carriers in the US supported IPv6. I don't think any carriers here in Ireland do.
My gigabit fiber provider only supports IPv4. Granted, they're just a VNO, using PPPoE on top of Eircom's network. Eir supports IPv6 if you subscribe to them directly, but their customer service is nonexistent and you'll be waiting over a year just for them to hook you up. For now I stay with the VNO because they have excellent customer service, except for not having an answer for me every time I ask them when they'll support v6.
That said I don’t feel there is any meaningful technical barrier to using 240/4.