The only software that is written without concurrency in mind is software that uses very few resources.
Anything else heavily uses concurrency in all kinds of ways.
which turns out to be the vast majority of software, because contrary to what the author of the paper predicted, single thread performance ended up being more than good enough (and not the bottleneck)
which turns out to be the vast majority of software, because contrary to what the author of the paper predicted, single thread performance ended up being more than good enough (and not the bottleneck)