Is bitcoin better money because of those properties? Sure. Are those properties a requirement for money? No. History is full of moneys that didn't offer much but were still highly used. Is a global unified ledger a requirement? No, you can have sharded ledgers everywhere. They can all be different from one another. Does it exist today? No. Could it exist? For sure. Do we know how to build it? No. Just because things are the way they are doesn't mean that better things cannot exist. I don't know if we will see something better than Bitcoin in my lifetime, but there is no mathematical proof that a better system can't exist. Let's give it another 100 years and check in later. My bet is that Bitcoin will last as long as other global reserve currencies have lasted. Then somebody will have a true new idea.