Also Ruby had a far smaller deployment and library base to convert. Get Rails and Sinatra ported and you're mostly there. There are as far as I know no significant commercial software that ships with ruby as its main scripting language. Ruby doesn't really have its equivalent of numpy and friends which has snaked its way into critical software in just about every field you care to mention. Ruby 1.8 -> 1.9 was more like Python 1.X-2.X