I think rubys TDD culture at the time also probably helped. My (purely unsupported) opinion is that the test suites were likely more fleshed out on ruby so its

I think rubys TDD culture at the time also probably helped. My (purely unsupported) opinion is that the test suites were likely more fleshed out on ruby so its less of a risk to switch. That said, I still saw lots of 1.8.6 installs in the wild for quite some time after 2.0 hit.