It's really, really hard to sell someone on a non-standard implementation of a popular language like C. For example, I've had customers beg me to add an extension to C. I implement it, and present it to them. They refuse to use it - because then their code would be dependent on a non-Standard feature.

The solution (for me, anyway) was to create an entirely new language. The changes that nobody wanted in C (not because they were bad, but because they were non-Standard) found plenty of traction and users in D.