Yes, but attacks are not technical, but political and economical. The intent is different and that's key in this conversation.
When miners collude to change transactions or prevent transactions, you've lost your immutability and censorship resistance. That's different than two miners finding a block simultaneously and then it becoming a game of longest chain wins.
What I'm trying to say is that BTC is immutable in the same sense that ETH was immutable until the DAO hack. In other words - not at all.