By Moore's Law, we can expect hardware speed to be 10 times faster in 5 years and 100 times faster in 10. Even if Bitcoin grows at crazy adoption rates, I think computer speeds will stay ahead of the number of transactions.
Did it increase by tenfold in 5 years? Not even close. Satoshi did not have the adequate data here.
There is a lot of processing power being untapped right now. This is typically found in GPUs though:
The max radeon single card (not a 2x) of 2008 was, the 4870 doing
1.2 TFLOP (single) / 0.24 TFLOP (double) / 115gb/s ram
The max radeon single card (not a 2x) of 2015 was R9 Fury 9 doing:
8.6 TFLOP (single) / 0.53 TFLOP (double) / 512 gb/s ram
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Data from:
https://en.wikipedia.org/wiki/List_of_AMD_graphics_processing_units---
And two imgs from NVIDIA (2-3 y. old but anyway)

