Demand will also grow as technology matures, if that maturing means more efficient and cheaper models. We're already at a stage where only a very small niche cares for better more complex models.
But which companies will capture that value? It could be like semiconductors where TSMC makes most of them but captures very little of the value.
People keep repeating this but is it true? In natural sciences, for example, there are endless applications. Anthropic models have only recently reached the level what I would call useful. Still, they are far from perfect and there's a lot of room for growth. Is science a very small niche? I don't think so.