The other argument I’ve seen is technological … where the major corporation starts influencing the software to their advantage … over time enough software changes are made so that the ecosystem becomes dependent on those changes … developers keep getting nudged, encouraged or influenced to make changes or upgrades to accommodate corporates and their systems … then once enough changes have been implemented, the whole system becomes dominated and controlled by the corporates.
If they can’t achieve instant take over, they don’t mind playing the long game and slowly dissolving and eroding the fediverse over time.