Unity has temporarily closed its offices in San Francisco and Austin, Texas and canceled a town hall meeting after receiving death threats. The company made the call as a precaution against possible retribution after it announced a contentious change to its business model this week.
Big corporations need service contracts. If something in the engine is broken where it impacts the game in development, engineers are flown in to fix it at the customer’s site (if that’s necessary). That’s not something available with most open source tools.