The number of SBOPs per FLOP has not been constant over time, and it isn't really obvious how
that's going to change in the future. Remember you have to account for all of the control
infrastructure, which dwarfs the arithmetical logic on a modern CPU - thousands of
multiplexers, comparators, buffers, lookup tables, signal repeaters, etc. just to get the data
from memory to the ALU and back - and the trip gets farther every year. I suspect there are
more like 100k SBOPs per FLOP in a typical CPU, but that's a guess.
Will things get more or less "efficient" over time? It's very hard to say, there are powerful
forces pulling in both directions. I'd say the biggest undetermined aspect is whether we can
weasel around Amdahl's law, or how much. How parallelizable will the software running on the
ultimate laptop be? If everything ends up being highly parallelized, microarchitecture is
likely to evolve towards simplicity and SBOPs per FLOP will probably stay roughly the same or
even come down a bit. If nobody comes up with a way around Amdahl (which is a rigorous
theorem unlike Moore's "law"), single-thread performance will need to be continually
increased, and that will increase SBOPs per FLOP over time.