I've seen breaking changes between Ruby 1.8.6 and 1.8.7, so I'm really suspicious of this claim. Start with which version of Ruby are breaking changes not to be expected until 3.0?
Ruby doesn't follow SemVer, so expecting no breaking changes between 1.8.6 and 1.8.7 wouldn't necessarily be correct. I don't remember what the policy was at the time.
i feel ruby's syntax is mostly done. an addition here or there, but breaking shall be rare as it just feels so finished. performance wise i think it can use (and gets) a lot of love.
on the python side things are different. python seems quite a bit faster then ruby. same league, but faster. yet its syntax is what needs to be greatly improved upon as it is so full of surprises and dark corners.
a language's syntax it's like its API, and performance is an implementation "detail". breaking the API is much more painful then chaning the implementation -- therefor i prefer ruby's approach: begin slow but with a quite stable syntax.
p.s. i dont intend to hurt feelings with this comment
Well, i mean, there were backwards incompat changes in ruby 2.0, which I think is after he said there woudln't be. They were fairly minor and easily dealt with, but there was certainly some software that had to be adjusted for ruby 2.0 from 1.9.3.
I don't expect this to actually be true, but it speaks to an attitude.