As long as there is the option to do differently within the current system, or ways to improve that on a different layer, I don't understand why you'd classify this as a definitive failure.

You're still free to mine on the network, without having to ask for permission. You're still free to run your own node / set up a better solution.

And as for privacy.. Bitcoin never was intended as a solution for privacy issues. 

 Do you even read satoshi notes on foruns about the implementations he was trying to implement on bitcoin that was implemented on monero? 

https://image.nostr.build/734bb5301d46a3600132d6b0df758cddfb28ccd1d99989a4bf98ad3088e842ff.jpg 

 That's great. There was clearly an intention to improve upon the privacy aspect. However, this being a way to improve upon Bitcoin, rather than being at the core of Bitcoin since release, shows that it was not main issue that was being solved for here.

Monero may have gotten better privacy, but at what cost? Surely a trade-off was made.