Obviously, performance is important; however, there is huge difference in the engineering cost of splitting your codebase into 2 languages and upgrading a langu

Obviously, performance is important; however, there is huge difference in the engineering cost of splitting your codebase into 2 languages and upgrading a language version in both the short term and long term. A 17x speed up in code doesn't guarantee a 17x speed up on future iterations of their product. I am not saying they made the wrong choice; it seems like what they chose worked for their use case. It could have been the case that 2.6 didn't work for their needs, but I think it's still worth an investigation.