Ruby is perl-minded folks reinventing python without understanding it. The result was: ruby is python-done wrong.

Now comparing python flask uwsgi and jvm jetty apps are in favor of python in all metric.

Starting a django elephant takes no time compare that to starting less capable framework of choice in java world.

To be fair, java can be much much faster than python. But usually you don't care because python is not the bottleneck. Ex. The bottleneck can be in the SQL query