Facebook faces competition from Twitter, TikTok, Reddit, Twitch, YouTube, Discord, Steam, VRChat, dating apps, Netflix, etc. They deal in attention, and there are a lot of attention seeking companies. Even in the social networking space.
I'm not defending the company by any means. I'm just pointing out the landscape.
The companies most applicable to break up scrutiny are Google, Apple, and Amazon in precisely that order.
Google owns the web. They control search. The desktop and mobile browser space. Web standards. The ads marketplace. Google Play and the associated profits. They lock people into their ecosystem of store, messaging and productivity apps, and force competitors to play nice using this leverage, despite Android being "open source". They're trashing the quality of the web for profit maximization and extorting advertisers. They're trying to strong arm all of the web into a hosted AMP-like platform that Google serves and controls.
Apple owns 50% of the mobile market and keeps it under a tight grip with rules and taxes. They have a deep ecosystem of hardware and software that only plays nice with itself. They're anti-repairability, anti-portability, and treat their platform as a Berlin Walled dictatorship. They drag their feet on web standards and don't allow any edge for competition, meanwhile they grow into the payments, ads, healthcare and other spaces. They've grown a protected republic that is 50+% of domestic computing. If you launch a business on Apple, you'll owe them 30%, must play by their rules, can't build a customer relationship, and will probably wind up competing with them. And when Apple wants to compete with an offering a small company in their app store has, they ban or remove them. As much as we hate ads, they can destroy billion dollar businesses with simple policy changes, acting as a gravitational wave proportional to the scale of their business.
Both of these companies frequently get caught colluding on labor and anticompetitive pacts.
Amazon treats its sellers like shit and copies the ideas that work at scale. They horizontally integrated to the point that they run half the Internet, a major grocer and food retailer, consumer electronics, logistics and transportation, multiple film studios, video gaming, etc. There's nothing their hands aren't in, and due to economies of scale they can push anyone else over. If you host on AWS, they're offering deep discounts to their internal competitor. They're also turning all of open source into "free labor" for Amazon and using it as a tool for lock in.
Each of these companies could easily be split up. Amazon probably the easiest, because it's plainly obvious where most of the business divisions lie. They're into everything. Apple the most difficult - maybe forcing them to open up their platform and divest of media interests is a better action.
This wouldn't be about about destroying value. It's about making our economy robust and resilient. Giants are not conducive to that as they can price out actual economic activities and innovation.