Google says per-transistor chip costs stopped getting cheaper 10 years ago, but how is that right?

Taiwan Semiconductor Manufacturing Co. wafers.

GPU prices remain painful. On that we can all agree. But can it really be correct that the per-transitor cost of chips hasn't budged in a decade? So said Google's Milind Shah last year, according to Semiconductor Digest (incorporating Memory Buses Weekly, or at least it ought to!). 

More specifically, the claim (via Tomshardware) is that the cost of 100 million transistor gates within a chip are about the same today as back in the 28nm generation of silicon. In fact, according to Google, today's 5nm and 3nm chips are actually slightly pricier per transistor.