Not exactly impressive, nature is famous for calling it quits once something works well enough. Anyone who wants to can create a non-biological neuron/axion connection that runs orders of magnitude faster. The real question is "but does it actually do something" because that's where nature shines pretty well.
> nature is famous for calling it quits
Yes, evolution builds upon what went before rather than starting fresh, but nature never calls it quits. It's a process, not a thinking entity. In any stable population there will be variances that have neither a benefit or cost until environmental pressures force it to "select" the most appropriate. You have to look at a longer timescale to see the adaptations take hold.
You could say species dying out is calling it quits in a way, but evolution encompasses everything not just the extinct - but I don't think that's what you meant.
Hence calling it quits: nature will do what it needs to do until things work well enough, and then calls it quits for that particular feature set until such time where what used to be good enough isn't good enough anymore.