The previous implementation of DOCSIS 3.0 could do 108mbit up, Virgin chose to roll with 12mbit, the revised spec is capable of 150mbit up, again Virgin decided to choose headline download speeds because it beleives that the market is still driven by headline speeds (and it is). 3.1 is capable of 10G/1G at present, by the time it's adopted it could well be more than that as we saw with 3.0. VM is and always has been a closed platform, even with Liberty Global at the helm now content distribution and opening up the platform hasn't happened, they also seem to be holding back on 4K as the whole thing has stagnated since TIVO, i'd look to the US to see where that's going, also I don't see them being in a hurry to do 10:1, but i'd like to be wrong.
The BT side of things will see G.Fast bring 300ish/50 to the rest of us initially with the option of 500mbit down and is slated to start roll out late this year or early next year - one of the trial's is just down the road from me. We'll see G.Fast along with FTTdp to bring it in range of the home, once it's at a dp within 350m then FTTP becomes more realistic, but I agree unless you have a lot of money and/or live in a FoD area that's a decade away.