The best players usually don't make the best coaches.
The point guard on the Portland Trailblazers NBA basketball team recently hired a shooting coach to help him with his shot. The guy he hired never played pro basketball and he didn't do much in college. However, he's a good shooting coach, partly because he knows what it's like to lack the natural ability and gifts of the best players.
The same idea applies to content creation. Contrary to what you'd expect, the "people who know" in your company may not be he best sources for content. Despite being so good and knowledgeable, the experts nevertheless likely lack the ability to teach what they know. And, because great content often involves explaining to people who aren't as knowledgeable, your experts could be the main obstacle that keeps you from creating a steady stream of content.
An obvious solution to that problem is to ask people who are new to your company to write content, which would also help them learn more about your products. You'd certainly want to edit what they write, but at least you'd get some good content churned out.