Due explicitly to market behavior unless regulated otherwise, exactly. Most people who build companies do so to make money. When you accumulate enough capital/power, it just becomes good business to use that power to cannibalize your competition if you're able.

What is good for modern business, profit exclusively, becomes explicitly detrimental to the society that provided the infrastructure and conditions for that business to succeed in the first place, which is why such behaviors need to be but are not prohibited.

At this point, our society exists to grow our beloved economy, when the reality is an economy is supposed to just be a lowly tool to better distribute goods and services for the benefit of society and it's citizens.

https://www.cnbc.com/2021/10/18/the-wealthiest-10percent-of-americans-own-a-record-89percent-of-all-us-stocks.html

Most stakeholders of American society, its citizens, are not meaningfully among the shareholders our society labors to benefit. The most maddening part are all the exploited Americans who would literally die defending the current system and their own exploitation and that of their family in the name of tradition/blind faith/sunk cost fallacy/the schadenfreude of "I suffered so you should too"/ etc.