The pricing has way more to it than "because gamers will just buy it." The majority of gamers won't buy a $600+ chair. That's way there are different pricing segments. There are already decent chairs to be had at these price points as long as you keep your expectations in check.
One thing people neglect are warranty programs. Herman Miller and Steelcase chairs come with a 12 year warranty. Any chair you buy should come with a decent warranty. At least 5 years and/or a limited lifetime warranty. They are more expensive because they are built to last a long time.
Cheaper chairs that come with a 2 year warranty with bo option to upgrade to 5 years are ones to stay way from. If a company can't trust their chair for more than 2 years then it makes me question their craftmanship and trust in their product. But usually these companies design these chairs that way in order to get repeat purchases in the next 4 years or so.
Another thing... a large portion gamer/office chairs all come from the same manufacturers in China like Carn Brea, DXBOS, and whoever IKEA uses. These companies just slap their branding on the chair and add a $200-$400 price tag. It keeps production costs down and allows to have a higher profit margin.
Companies like Knoll, Steelcase, Herman Miller, Humanscale, etc. are manufactured in locations where workers are paid higher wages and have stricter labor laws. Also material quality is usually higher grade. So products from these companies tend to be more expensive.
In the end people can either afford or not afford to care about build quality, fair wages, and labor laws. Some people just don't care about any of that no matter what. So go with whatever is most comfortable for your price point. Just be smart about it and, if it is within your means, opt in for a 5+ year warranty if they offer it.