Ethereum is transitioning to proof of stake which means the nodes will run on raspberry pis. At any rate, if you think data centers are burning the planet, you really should boycott the internet. Its data centers and mainframes all the way down.

Stake is better than work, but it also forever installs a system where the rich get richer just for being rich.

If you think these defi projects are hurting the environment then you have not been paying attention to the industry. Proof of Stake, what most smart contract tokens are moving to, is very energy efficient.

Is anyone actually really sure that Proof of Steak is secure though?

Anyway, none of this matters because Bitcoin exists and is the dominant shitcoin (due to first mover advantage). All these other shitcoins can claim whatever efficiency, but it doesn't matter because that's a very isolated view of the problem. The shitcoin economy as a whole will still be fueled by mining unless somehow Bitcoin gets dethroned and the whole mining thing just goes away. I can't imagine that happening without the whole economy crashing completely into the ground – but that would bring all these efficient coins down with it.

Yes, they've been live for years. Bitcoin can't do smart contracts, it's not a Turing complete scripting language and it's very difficult to work with, so of course it matters.

And already more transactions and more daily volume is settled on Ethereum than Bitcoin, see https://money-movers.info/ and https://cryptofees.info/ (pink lines are Ethereum DeFi applications)

This is my first time hearing the moniker "shitcoin". Thank you :D