It doesn't control my node. That's all that matters. 😁

If Blackrock changes anything, and it can, it can make the total supply 100 billion Bitcoins if it likes. It can change the consensus mechanism from PoW to PoS if it wants. It can spin up as many nodes as it wants. It can control as many miners as it wants.

I just don't update my node to the version they're making changes on. Because it's not Bitcoin anymore.

The supply issuance on the chain that I use, supplies blocks every 10 minutes and the mining difficulty changes every 2016 blocks - depending on the amount of hash power on the network determines how difficult it is for the rest of the network to mine blocks. So Blackrock can spin up as many nodes and as many miners as it likes - they're doing me a favour by making my coins more secure.

Your turn..