I understand your "what if" scenarios, but this is an existential crisis that needs to be resisted against with all instances working in concert. This is not a "what if" scenario. This is the actual iceberg and it is big enough to ruin the fediverse for all instances, no matter their affiliation with the garden.
So, we either unite to defend the independence of the fediverse, or we let a corporate giant take it by ovewhelming us with their "important updates for your security" until we are all assimilated.