Generally, competition is very essential in a free market and without competition, there would be monopoly in the production of goods and rendering of services. And when theres a monopoly, small business and start ups are destined to fail.
In a free market, economy competition is vital for its growth. This keeps price lowers, force companies to improve product quality and services, and fasten innovation. On the other hand, it could destroy local businesses because of the investment of foreign companies. Local small businesses and factories were forced to shut down because of their small resource. Though there are some disadvantages, a free market economy plays a vital role to increase a country's GDP growth.
But the idea is true, if you end up with something that profits you just a bit more, you do that. Like for example if you create a product and put it on sale at amazon, then amazon sees that you sell a lot of it, they can create their own product that could compete with yours, similar thing, and then ban you from selling yours, making them the sole seller of such a product. Is this fair? No, but is this legal? It is.This is how competition gets screwed, small business gets screwed by the big business, and while you were selling it for 9.99, they took over and banished you and now selling it for 19.99 however they want.