The work to get 10nm working also applies to 7nm and perhaps 5, wouldn't make sense as they've chucked bazillions* at 10nm already.
*I have no idea how much exactly
Even if they chuck 10nm away that won't have much impact on their 7 and 5nm development - obviously lessons learnt on 10nm can be valuable. 7nm was forked from 10nm years and years ago with Intel working with Nikon and ASML, etc. for EUV tech towards that end over 10 years ago.