The problem with that analogy is that you are comparing darcs to a myth. Postgresql was not "very slow at first". It has certainly gotten faster, but it was f

The problem with that analogy is that you are comparing darcs to a myth. Postgresql was not "very slow at first". It has certainly gotten faster, but it was faster than mysql for real workloads ~15 years ago. It isn't closing a gap, it is pulling further and further ahead. Mysql is only fast if you are using myisam tables and doing a single threaded microbenchmark of repeating a single simple query in a loop. On real benchmarks where there's many connections executing many different queries at the same time, postgresql has always been way ahead of mysql.