It's because anti-trust laws aren't well-equipped to deal with modern monopolies.
the US's legal framework for anti-trust come from the Sherman anti-trust act of 1890 and the Clayton anti-trust act of 1914 (note the dates). The jurisprudence basically holds that being a monopoly isn't illegal per se, but what's illegal is abusing consumers - traditionally the cause of action in anti-trust lawsuits are that a corporation does something anti-competitive to increase prices. Facebook is mostly available at no cost to consumers (or at least, consumers don't have to pay to use the products) and so they avoid anti-trust scrutiny.
To see it in practice, check out [1]. Some Japanese auto part suppliers were acting in an anti-competitive way and what got the DOJ so chuffed was that consumers had to pay more for cars and car parts because of the behavior.
The Yale law journal has a great expose on the tension between our 19th/early-20th century understanding of abusive monopolies and the realities of 21st century commerce [2] and basically the core issue is that anti-trust laws are powerless to stop a company from acquiring the power to become an illegal/abusive monopoly.
The EU has actually been much more skeptical/hostile of the arrangement between Facebook/Instagram/Whatsapp , and the best legal thinking on using anti-trust norms to break up big tech comes from the EU. Unfortunately, I don't know much about it and I'll invite any expert to weigh-in.
the US's legal framework for anti-trust come from the Sherman anti-trust act of 1890 and the Clayton anti-trust act of 1914 (note the dates). The jurisprudence basically holds that being a monopoly isn't illegal per se, but what's illegal is abusing consumers - traditionally the cause of action in anti-trust lawsuits are that a corporation does something anti-competitive to increase prices. Facebook is mostly available at no cost to consumers (or at least, consumers don't have to pay to use the products) and so they avoid anti-trust scrutiny.
To see it in practice, check out [1]. Some Japanese auto part suppliers were acting in an anti-competitive way and what got the DOJ so chuffed was that consumers had to pay more for cars and car parts because of the behavior.
The Yale law journal has a great expose on the tension between our 19th/early-20th century understanding of abusive monopolies and the realities of 21st century commerce [2] and basically the core issue is that anti-trust laws are powerless to stop a company from acquiring the power to become an illegal/abusive monopoly.
The EU has actually been much more skeptical/hostile of the arrangement between Facebook/Instagram/Whatsapp , and the best legal thinking on using anti-trust norms to break up big tech comes from the EU. Unfortunately, I don't know much about it and I'll invite any expert to weigh-in.
[1] https://www.justice.gov/opa/pr/japanese-auto-parts-company-p...
[2] https://www.yalelawjournal.org/note/amazons-antitrust-parado...