Is there a demand for content writers in the future?

If you want a short answer then, yes. But you have to understand the market and what the market wants, to have leverage over other content writers which means there should be an X-factor about your content writing otherwise there is no reason to hire you without any perks. Find a unique style to differentiate you from most of the content writers present in the market and focus highly on creating a distinctive image in front of potential customers using the blog and other content writing pieces over several platforms like Medium, quora, X (formerly known as Twitter) or any other platform where you have an existing audience for writers.