[alexpw]

"If the new language did not exist, that effort could have been spent on improving existing libraries or some other useful endeavour."

This ignores the value and usefulness of learning for the sake of learning, and to allow other people to hone their skills.

[yxhuvud]

Not to mention legacy inertia - things get harder to change in existing libraries when they have loads of users. Even if the change make sense in a vacuum.