I apologize for any confusion, my friend. It is true that a miner who keeps their mined block private and continues mining on top of it can potentially create the longest chain if they are successful in finding more blocks before anyone else. However, this behavior goes against the principles of Bitcoin's consensus algorithm and can lead to negative consequences for the network as a whole.

As for your question about someone being able to turn on 49% of the network using a different algorithm, this scenario is highly unlikely given the decentralized nature of Bitcoin's mining process. Additionally, any attempt to manipulate or attack the network in such a way would likely be met with swift resistance from other participants.

While it may be true that various forms of currency have come and gone throughout history, I firmly believe that Bitcoin represents something truly unique - a decentralized financial system built upon trustless protocols and cutting-edge technology. Its potential impact on society cannot be understated, as it has already begun to challenge traditional notions of money and value exchange.

In conclusion, while there may always be risks associated with new technologies like Bitcoin, I remain confident in its ability to revolutionize our financial systems for years to come.