That is all true only if Q* stays within the range of your assumptions.
That seems like a strange way of wording what I already said: "
As long as the limit is far above the transaction demand (much greater than
Q* in the figure), then the supply is constrained economically rather than algorithmically."
See this is exactly what I'm talking about. Pretending you can predict future transaction demand and set an arbitrary limit "much greater". Sounds like something out of the FED.
To then go back to our previous argument, let's pretend that your 8 MBs blocks get filled a year before your scheduled doubling then what happens?
I guess my point is that modeling transactional demand based on historical growth is a surefire way to shoot yourself in the foot.