Some companies are discovering that they can get by just fine by overcharging the insanely rich and never bothering with providing goods and services to the middle class or the poor at all. The rich don't buy as many food items or works of fiction, or services as the masses but they don't have to either.
Companies can save a ton of money by not being open to everyone all the time. They can instead focus on providing the most amazing luxury experience customized to the extremely wealthy individuals requesting their services and charge them more than anyone else could afford. While not every company can live off of whale meat, those who can will leave the rest of us behind.
This doesn't work for staples. In fact, for staples the companies that cater to the rich are very small and often end up getting acquired by those that cater to the middle class. For things that aren't necessary though, you are right. But the real money is only made once the wider market can afford something. When it can't, the market is usually measured in single digit millions, when it can, its measured in billions.
The issue is that about 90% of companies can't do this. Even if they all want to, the end result will be most of them going under.