I need to point one thing, everything has a `speculative value driven by supply and demand`, and supply and demand are people. With our trades, holding we make supply higher or lower, people that want to buy are demand. People give value to everything around.
We are not moving towards centralized private blockchains, governments do that, and some private companies, why not if they want private network, but as the customers and users we choose to use them or not, we can choose decentralized bitcoin over centralized ripple. 20 years ago nobody knew what is decentralization, everything was centralized, blockchain is a step forward not backward.
20 years ago the Internet was more decentralized because there were no big sites. Today Google, Facebook, Twitter have a huge share of Internet users. And when information becomes centralized, it's easier to control it.
Also, those private blockchains aren't meant for consumers, they are used internally and between companies. Coins like Ripple and EOS are not centralized private blockchains, they are centralized public blockchains, which is more dangerous, because they try to compete with Bitcoin and try to hide from users that they are centralized.