In the past the hub 4's were only sent out to customers on the 1gb connection, or to those in areas of high utilisation.
Info below published 21st October 2020
https://www.ispreview.co.uk/index.ph...ter-again.html
At the time the wider, albeit still very limited, distribution seemed designed to benefit areas suffering from weak WiFi or high utilisations (i.e. where local lines are being heavily used). The HUB 4.0 can bond 32 channels together, while the HUB 3.0 can only do 24 (i.e. the new router can be harnessed by those on slower packages to deliver an improvement, provided the operator supports the bonding change in those locations).