You're talking about individual companies, I'm talking about the systemic factors in general.
> They don't have to sell because the factories can't stop making products.
What are they supposed to do? Shut down the factories and fire their workers? Industrialised production relies on huge up-front investments and large operating cost, in exchange for enormous output and low per-unit cost of production. That's how it works in capitalism. That's how it works in communism. If industry can't operate on that model and need to get their income from fewer customers, then consumer goods would be much more expensive as a result. Also much better in quality, but inaccessible for the majority of people.
Mass media is also an example of mass production, working in the same way. Whether it's through subscriptions or selling physical media or entrance tickets, creators seek a huge audience. They usually have huge investment costs to produce their stuff, whether it's money or time. Then their cost-per-unit sold is extremely low, sometimes approaching zero. But if they can't get paid by a mass audience, then creativity will have to return to bespoke works. Ie, artists will make their work for rich individuals by commission, instead of to the general public.
> They don't have to sell because the factories can't stop making products.
What are they supposed to do? Shut down the factories and fire their workers? Industrialised production relies on huge up-front investments and large operating cost, in exchange for enormous output and low per-unit cost of production. That's how it works in capitalism. That's how it works in communism. If industry can't operate on that model and need to get their income from fewer customers, then consumer goods would be much more expensive as a result. Also much better in quality, but inaccessible for the majority of people.