It can end up being bad for both readers and writers in the long term. If writers aren't able to find profit in writing then there will be less people spending

It can end up being bad for both readers and writers in the long term. If writers aren't able to find profit in writing then there will be less people spending the time and effort to produce good writing, which in turn means less quality material for readers to read (and, as an aside, less quality material for an AI to train on in the future). We could arguably reach some type of feedback loop where less quality writing leads to less interest in reading, which leads to smaller reading audiences, which leads to less quality writing being produced, etc. People do love free stuff, but free stuff often isn't sustainable under our current economic system.