Because the Microsoft date sync it’s web browser you want to wipe out trillions in value to the US economy, projects that could never be done outside of a large company filled with the best aligned talent (custom chips, google search), and hand it over to the next willing coordinated massive player with entirely different values and regulatory laws (China)?
I think this is a very silly idea that would be super destructive and net negative for the world.
Those anti-competition laws are only applicable when a company is using market dominance to exclude new entrants, distorting the free market. Not true in this case. Lots of small companies are not inherently economically better than big firms. It totally depends on the maturity of the market in question. Large firms gain economies of scale, and can pursue opportunities with large upfront capital requirements.
The point wasn't about the competition. The point is that many small companies are better for an economy than a single large company.
Let me give you one small example: MediumCo and SmallCo each need 50 stenographers to get the office work done. When the two merge into MegaConHugeCo, it only needs 60 stenographers to get the office work done. "Economies of scale" are great for the giant new company, but throw 40 people into unemployment. That is bad for an economy.
Multiply that by all of the functions of a company, and you understand why the federal government and politicians put so much attention and resources into helping small and medium businesses.