No, the internet is not killing the art of writing but as you say changing it. having said that, I think there is a case to be made that some vested interests are trying to limit the scope of language. In George Orwell’s novel 1984 the author introduces the idea of “newspeak” a form of English which limits the ability of language to express ideas. I see some of the elements of Newspeak in the restrictions that politically correct thinking and the authoritarianism of illiberal liberals would impose on us.
https://originalboggartblog.wordpress.com/2013/04/15/the-orwellian-paradox-killing-you-for-your-own-good-15758522/