I worked on a Strattic conversion some time back - they basically scrape all your pages and serve them statically, but you do have to do some things to support search, forms, etc and you'll end up pruning plugins that don't work well with it.
But, serving static pages is very very fast afterwards.
I'll bet on future WP updates eating whatever perf improvements new hardware will give. Besides, Moore's Law is about the number of transistors. Speed - and especially single threaded speed which is what matters for PHP sites - is not going up nearly as fast anymore.
Yes, but practically speaking, waiting 20 years isn't an option. Moore's Law has stopped delivering rapid single-threaded performance gains and not everything is trivially parallelable.
The fastest single-threaded cpus today are only 2x faster than the fastest single-threaded cpus of a decade ago...
But, serving static pages is very very fast afterwards.