At some point something better than the S17 will come and the cycle repeats again. S15, S11, S9, S7. Everytime a new generation comes, this story repeats. More surprising is you didn't expect this after so many years of the same. You could go back to the days of CPU mining, then GPU mining, FPGAs, the first ASICs, etc.
More importantly at these rates we are talking 32 watt/th... vs 47 watt/th the M20 (12nm) or 60 watt/th for the S15 vs 70 watt/th the M10(16nm). Also take into consideration that Bitmain specs are probably better than reality, we will have to wait for an actual review from members of this forum.
MicroBT is still at 12nm, they could probably still make something even better at 7nm. Frankly if the S11 and S15 are 7nm parts, they are quite disappointing, considering a 16nm chip nearly matched them. Maybe they planned to finance the refinement by selling those low yield units first, or maybe there is an S19 lurking around the corner, how to know?
my thoughts are :
the s15 does
50 watts a th on low speed
60 watts a th on high speed
a 28% improvement =
36 watts a th on low speed
43.2 watts a th on high speed