Yeah, that surely wouldn't grind everything to a halt and effectively make the existence of non-megacorporations impossible.
No, what should instead be done is prevent the existence of these megacorporations which have disproportionate influence on humanity in the first place. Prevent them to form and chop up the existing ones aggressively into smaller ones.
I've long suspected that these "megacorporations" are nurtured for national security reasons, to consolidate and project power. The disproportionate influence is by design, a feature not a flaw. Especially since those who make the rules are owned by such powers themselves, including those responsible for intelligence (corporate spying, undermining workers unions) and regulation (not preventing Metalphabetamazons from dominating a wide range of industries).
This has at times been explicit policy. It's a big part of how Japan (re-)joined the developed world so fast after WWII—they gave a few megacorporations a captive home market to keep them healthy & safe, used incentives to get them to pool R&D money and share the output, then set them loose on foreign markets.
