I wish I could find that article again, it's just a claim in a comment at that point but that guy said his team rewrote a c++ system deemed first in class / world class (real time trading or something close) and unbeatable by its 30-years-in-the-field authors. Yet the F# (IIRC) was smaller AND faster, because they had better abstractions to describe the system, find and solve bottlenecks while the previous team members were drowning in c++ LoC and hubris.