With green energy, digital gold is a lot more green than physical gold. Bitcoin is like electric cars – not super green right in this moment when the grid is still dirty, but all it takes to make it greener is to green up the grid.
Meanwhile the classical banking system: uses all forms of transport which green up slower (armored cars, planes, etc), requires crazy amounts of construction (I don't even want to guess how much cement has been used in the construction of physical banks all over the world), all those buildings use energy for AC/lighting/etc, require huge amounts of manpower to manage trust in the system (people definitely aren't green), and also need their own datacenters anyway. And I'm sure I'm forgetting some things, where as with BTC pretty much all consumption is baked into mining, which again just gets greener automatically as the grid gets greener. Nobody is running a Bitcoin mining operation off of diesel generators. If you did the math (impractical given the breadth of the existing banking system), I think you'd find Bitcoin is already far greener than the existing banking system, by a huge margin.
And cryptos like Ethereum have the potential to 10x/100x/1000x that with things like PoS vs. PoW as well as the fact that Ethereum smart contracts can not only replace banking but probably other industries as well, such as title companies and various other middlemen.
It's been 13 years now and nobody's done it, because that's a terrible idea. The reason lawyers exist is that all contracts have ambiguity and require a human to review and consider. All contracts have circumstances that aren't captured. Just ask the DAO folks.
Middlemen exist for a reason. Efficiency, conflict and ambiguity resolution, and so on.
Blockchains are only useful for things that are entirely captured within the blockchain. As soon as you interface the blockchain with the outside world you have to trust something to enter and capture that data accurately - garbage in, garbage out. Once you're trusting someone, you don't need a blockchain, just fire up and RDS instance and save everyone the headache.
And with tokens that are tied to real-life things, the benefit is that once you've used real-world trust systems (e.g. real-life contracts / lawyers / courts / etc) to tie something to the blockchain, you can (going forward) hand everything over to the trustless and secure system. i.e. You tie your property to the blockchain once, and from then on you don't need to involve all those inefficient systems, you just transact the tied token directly on the blockchain.
Just because it hasn't been done successfully yet doesn't mean it's not viable. How long did the internet exist before [thing that is taken for granted on the internet now] was successful?
Finally, Ethereum launched in 2015, not sure where you're getting 13 years from.
But I see your point.
We should make a pyramid/MLM scheme where you're promised rewards for planting trees, segregating waste, cleaning up in any potential wildlife habitats, and reducing/reusing stuff in general.