Dog Eat Dog
When we say it’s a dog-eat-dog world out there, we’re talking about market competition. And the term comes from dog cannibalism. Like when dogs in the wild are reallllllly hangry, yes, they'll eat each other (albeit with a side of greens and some ketchup.) If you just made your product or service the best on the market, someone will no doubt come along and offer it at a lower price, or make it even better.
In the case of lowering prices, this could lead to a chain reaction of lowering prices (a.k.a. a price war), making prices juuuust low enough to make it worth staying in business, but definitely low enough that you can still compete in the market. This cuts profit margins, but is part of the “invisible hand” that runs the economy and keeps it going. And, oh yeah, keeps firms from playing consumers, like monopolies can do.
Although some would argue that many firms are then incentivized to take a walk on the dark side to stay competitive, which could mean lying to consumers or doing something else just plain unethical.