A private company will attempt to maximize profits, yes indeed (presuming they are a for profit company). The will have competitors attempting to do the same. They will all, in an open market, attempt to out do each other with better products at a better price thus becoming more attractive to consumers. If they fail, the consumer will let them know. It's a market driven economy, the "invisible hand" etc.
In a socialist world, the considerations won't be profit, which is an evil term, but keeping employees (voters) happy. Freed of competition (and the constraint of needing a profit), they are able to charge and make whatever they want, empty shelves or crappy products would not be a concern. This is a centrally planned economy, and the more it's planned, the worse it always is, in every case.
I saw it first hand in Cuba, and to a lesser extent in France, and to a lesser extent in the USA. Cuba was far worse than I expected. We only saw Havana and I thought they would have spiffed up the tourist area, but it was horrible, and our guide described her daily life, it was unpleasant. They had shops both government owned and privately owned, the do allow some small businesses to be private. There was a very obvious difference between them, I could tell which was which in seconds.
Free markets also can have issues, monopolies can tend to arise and thus you no long have a free market. Our government used to pay some attention to that.