Calls for breaking up companies make great headlines for politicians but let's look at the history and why this was necessary as a solution to antitrust.
The textbook case for the Sherman Act was Standard Oil. Built up by Rockefeller in the late 19th century, Standard Oil came to effectively control the extraction, refining, distribution and sale of kerosene (in particular). This is when oil pipelines began, interestingly to break up another monopoly: the railroads (for distribution).
Standard Oil split into a bunch of companies, many of which still exist today (eg Chevron, Exxon-Mobil). This break up actually made Rockefeller (even more) fantastically wealthy.
The key point is that Standard Oil could (and did) use its significant market power to squash competitors.
Another example: the Paramount decision that split film studios, distribution and theaters.
Personally I think very few Big Tech companies would warrant this kind of government action and top of that list for me would be Amazon, whose stranglehold on logistics, delivery and online storefronts is near-total. Amazon's delivery prices (FedEx, UPS, USPS primarily) cannot be matched. The barrier to entry is so huge, no one could reasonably compete.
But Facebook? Let's look at the last 10 years. FB bought IG when (IMHO) IG represented an existential threat to FB. So if you're going to argue market dominance, you're going to have to explain how a company a few years old with 13 employees (at the time of acquisition) could possibly threaten FB.
Another is TikTok.
Can we stop applying standards developed for 19th century oil producers to Big Tech where distribution is essentially free and said companies exist only so long as the users want them to?
I know it's trendy for lawmakers to bang their drums about an issue as a kneejerk reaction to grab some headlines and that they must hurry to do so before the market just solves the problem anyway but still.
Disclaimer: Ex-Facebooker. Opinions are my own.