It sounds like 7nm and 5nm are entirely feasible, but nobody is prepared to spend $10Billion on the fab until they're sure they've got (close to) the best solution.
Also, I feel like the whole industry is getting a bit lazy. The big foundries are all around 28nm and getting 100 percent utilization of their capacity. So long as their customers competitors have no better foundry to go to, there is little incentive to press forward. There is the possibility to fall behind, but waiting just means increasing certainty in the path forward. Meanwhile Intel...
That will change if/when intel gives up sticking to x86 only. Then anybody who has space and power constraints (hint: mobile) will be playing fabs off against each other.
Also, I feel like the whole industry is getting a bit lazy. The big foundries are all around 28nm and getting 100 percent utilization of their capacity. So long as their customers competitors have no better foundry to go to, there is little incentive to press forward. There is the possibility to fall behind, but waiting just means increasing certainty in the path forward. Meanwhile Intel...