When the deplorable practices become so widespread that they become the norm (amongst the majority) then the language has been proven to have evolved. Before that it is evolving - the example given becoming more widespread.
"ink" instead of "ing" and "ff" instead of "th" have not become the norm - far from it - and they are not part of a regional dialect. They are used by people scattered throughout our society who are too ignorant or too lazy to speak properly. I don't see them as becoming an accepted part of our changing language because they have not "evolved" to be any more acceptable now than they were 100 years ago. (I remember my grandmother expressing her abhorrence at such utterances.)