In the next few decades, this may be true. No altcoin or technology can threaten bitcoin's leadership position but in the more distant future it is difficult to say.

In all fairness, bitcoin is a product and result of technological development. Meanwhile, as we all see, technology is constantly evolving and even evolving extremely rapidly. So it's hard to know what will happen and we shouldn't be surprised if something outperforms bitcoin in the future. But like I said, that's not going to happen anytime soon, so there's no point in thinking about those things right now.