An author who remains trendy is at risk for having writings that will soon be out-of-date. Fresh writings, like fresh vegetables, are appealing and tasty, but may soon be unreadable as rotten vegetables are inedible. Note that a consumer who insists on eating only fresh vegetables is, at least in the temperate parts of the world, dependent on inexpensive air transport, and likewise, a trendy contemporary writer is dependent on telecommunications technology. A simpler approach to both food and writing may, in the long run, be more practical and less influenced by outside factors. Our ancestors ate fresh fruit and vegetables when they had them, but developed techniques for storing food for long periods. Some methods of preservation are crude and unpalatable, but consider also condiments, spices, cheese, cooking oil, candy, preserves, vinegar, wine, and liquor: many of these actually get better with age. Some writer's works remain readable for decades or longer, and some, due to the perspective that only time can give, may also get better with age.
Human language is amazingly flexible: the number of idiomatic, grammatically correct, and at least plausibly meaningful English sentences of ten words or less is vast (even with a simple vocabulary), and the variety inherent in a few such sentences exceeds the estimated number of atoms in the universe. We ought not be surprised, since ancient thinking has long insisted that the realm of the spiritual far exceeds the limits of the material world. Therefore, there are practically no limits to the variety of writing that is possible: just consider the variety of language from the ancient poets, even when they used a strict meter and rhyming scheme.
So, the contemporary writers who complain about the difficulties of their art, are severely limiting themselves by wanting to use popular language phrases. Staying hip, after all, is a full time job, and takes up precious time that otherwise would be used for actual writing.
The solution is to not be hip.
That does not mean that a writer cannot comment on popular trends, nor does it mean that a writer ought not be clever or witty or masterful in using style in language. But what is more important? Is it the language itself, or is it the information that the writer intends to convey to the reader? Certainly, our ideas — information — is incarnated in the flesh of words and grammar and so language remains a practically inescapable material intermediary between us and the realm of intellect. So style in language is useful and necessary, but it is not the most important thing.
The writer G.K. Chesterton, who is popular in Catholic circles, remains readable even after a century. His language hardly seems archaic compared to some of his contemporaries, for even though his writing is full of style, it is also clear. He commented on the popular trends of his day but did not embrace the popular, and so quickly-changing trends of language. Of greater importance, his emphasis was on ideas: these do not change, although they may be expressed in various fashionable ways with language.
A writer, I think, for the sake of his reader, his art, and even his own psyche, ought to have a conservative and clear approach to language. This does not mean that he ought to embrace the status quo, nor does it mean that he ought to dumb-down his language or concepts. It just means that he ought to be understood.