I’m not even sure there’s a counterfactual world where GE is a $m trillion business: The global economy has largely evolved beyond these massive, diverse conglomerates, and likely all to the good.
What does a “wow, GE really has been managed wonderfully since 1980” story even look like? I imagine they split up much earlier, each spinoff establishes their own brand, and there’s no “GE” to talk about.
Problem is usually these spin-offs happen because it becomes clear the parent org has been doing something nasty that's going to create tons of legal liability, and the spin-off is really protecting the parent from lawsuits.
DuPont is in the news recently with how they did this with PFAS pollution. Sure, sue the "PFAS company" into oblivion, but thankfully the PFAS polluter is no longer DuPont or DuPont investors. Not DuPont's problem that Teflon pan sales can't make up for the costs of all the associated environmental cleanup.
This happens frequently with pharma companies when internal testing shows there might be some long-term side-effects before it becomes clear in public studies. I think I remember hearing this playbook was used with asbestos back in the day.