FTTP is actually available in all the speed variants that FTTC is and additional ones.
So it seems that only BT Retail have figured this out and thus are happy to supply a service.
So for example 40/10 on FTTP is the same price as on FTTC, but the big advantage you know you will connect at 40/10 and not have any DLM training etc
The handover at the telephone exchange is identical for FTTC and FTTP, and even the same routers should work, as the presentation via the openreach hardware in the home is identical. So if Sky and TalkTalk are not selling it, then its because they've not got their heads around FTTP or believe it is of such limited availability that it is not work selling