>> I read the btopenreach interview that they stopped it.
No, they just disabled it from being permanently on. Read the bit in red I quoted from the interview.
G.INP Mk 1 had upstream g.inp enabled by default.
G.INP Mk 2 is upstream FAST by default.
The issue with G.INP Mk 1 was that there was a lot of modems which weren't capable of performing upstream G.INP.. so enabling it by default caused them problems.
The 2016 ECI roll out saw different issues, but those only affect ECI cabs, so atm G.INP is disabled in both directions for ECI cabs.