You're talking about startup time, which is bad in this case because of the overhead Rubygems introduces by adding loads of directories to the require load path

You're talking about startup time, which is bad in this case because of the overhead Rubygems introduces by adding loads of directories to the require load path. Pre-rubygems, everything lived in a traditional $PREFIX/lib/ruby/{,site-ruby/}$VERSION/ directory just like Perl and Python, and startup times were much more comparable. Atwood is talking about general runtime performance, and comparing it with the fast, mature JITed VMs that drive CLR languages. Python (and indeed other languages in its class) compare just as badly there.