One aspect I haven’t read about: competitive pressure and economics of scale.

So, imagine two carpenters: they both produce one chair a day. They sell it and can sustain their families with that. Now the one carpenter works a little overtime and uses sharper tools: he’s able to produce two chairs a day. He still needs only to sustain his family, so he could sell the chairs at 50% discount. But he goes for 75% of its original price. Still cheaper, he has more.

Everybody wants to buy those chairs now: they’re the same, but one is way cheaper. The other carpenter loses business, he can’t sustain his family anymore, because he needs to sell one chair a day at least. To keep up, his business needs to grow now.