18 month or 24 month, this is not very important. I was essentially talking about the fact that the cost per transistor was steadily going down, which is almost finished now.
Is there any data on the cost per transistor not going down? They seem to be able to pack an awful lot onto chips these days, the current record apparently being Samsungs 1tb memory chip with 2 trillion.
I cannot find a source for this outside of HN, but I have read here that R&D costs to build the next generations fabrication plants double each iteration which limits the total number of sustainable independent chipmakers. Currently, only 3 are left (TSMC, Samsung and Intel) and they all might give up within a few generations when it gets too expensive to scale down further.