Has it ever been possible? Could we ever trust the printed word, paint on canvas, or a stone inscription? Humans have, as long as they have been able to call themselves 'human', used the latest technologies to spread lies, fakery and disinformation to further their religious and/or political agendas while feathering their own nests. And people have largely been gullible enough to fall for most of it. It's not a coincidence that the spread of the major world religions began not long after the invention of writing itself. And there are still billions of people in the 21st century that believe in the stories of some stone-age middle-eastern and asian goat-herdsmen simply because they happened to have the bright idea of committing their fantasies to clay-tablet, papyrus and parchment.
The 'problem' with generative AI is not so much the technology itself, but who gets to set the agenda of how, where and why it gets used. Just as it has been for other forms of disruptive technology such as the wheel, the stirrup, the reed pen, moveable type, the steam engine, radio, television etc. ad infinitum ...