As noted by @Zarjaz - Openreach will basically want to be able to offer the entire "farm" on XGS-PON - this includes all the existing and perhaps 'legacy' speed tiers to their ISP customers.
As a pure wholesale network, they would not want to put themselves in a position where a technology change, means that they can no longer service all possible clientele.
(I do realise that they can run GPON and XGS-PON on the same bit of glass just on different non-interfering waves - but that may be a transitory arrangement rather than long term steady state arrangement where they drop back to one active PON technology on the same network)
Edited by Pheasant (Sun 18-May-25 17:29:39)