Satoshi decided to distribute new coins to the miners, and back then that was a fair method to pick a random stranger, so I understand the logic behind it. But nowadays these block rewards don't go to random users anymore, they go to the people who are wealthy enough to own a significant share of the hashing power. Essentially it's making the rich people richer, and that's the exact opposite of what he originally envisioned I suppose?
In
the whitepaper it sounds more like an issue with trust. I dont think this was about fairness, but about an online payment system that does not rely on trust of a 3rd party.
Wouldn't it be much more fair to give miners only the TX-fees, and pay a reward to some random stranger (transaction) in that block?
No. I dont even see where this can be fair. If I invest the majority of (electrical) energy and hashing power, how is it fair that I dont get the majority of the reward? I assume here that the blockreward is still higher than the tx fee reward. What you are proposing has nothing to do with fairness. Everyone can "do less", but not everyone can do more. It would be just randomness who gets paid so everyone would do as little as possible while still beeing eligable to get the reward. However you want to determine that. 1 transaction every block? Or does each count? So the more transactions the higher my chance? Wouldnt that be the exact same thing (more money = more btc) you want to stop with your solution?
That way the initial distribution of coins is garantueed to be fair for everyone, since the coins are going to the actual users of the network (which includes also 'the poor'), instead of the big guys.
The "big guys" not only use this network they protect it. The more hashingpower the harder is an attack thus the higher is the value of BTC. Those who put their time and money into this make it what it is, yet you want to punish them? One could easily argue the other way around and propose that unless you have at least x TH/s you are not allowed to use the network since you are not contributing in a reasonable fashion to its safety.
Also those you call big are mostly big because they started early. They took a risk in supporting bitcoin and after a long time the coins are worth something. Why is that not fair? You could have been here. I could have been here. I didnt think bitcoin would work, because I didnt invest enough time in understanding what bitcoin is. "The big guys" did and they found flaws and helped correcting them. They contributed time, money, electricity, know-how.
The way this could work is that the random tx is picked based on the block hash (similar to how the dice sites work). So a miner never has influence on who receives the reward, unless they withhold valid blocks to influence the outcome, which gives them a major disadvantage compared to competing miners (who will publish the first block they find).
And to discourage users from spamming the chain with dummy transactions, the reward should be equal (or lower) than the total amount of fees paid in the block. This causes their EV (expected value) to stay the same, rendering spam useless.
This also discourages miners from including only transactions from friends, since the benefit of sharing the reward will be lower than the profit they could have gained from the extra fees.
At first sight such a scheme would be very simple to implement, and much more fair. The only downside I can think of right now is that the coins will be distributed more slowly than Bitcoin does right now. And to bootstrap the network there have to be one (or a couple) of empty blocks where the miner gets a reward. No big deal.
Could something like this work in practice? I have a feeling Im overlooking something fundamental, because it sounds to good (and simple) to be true, but I cant figure out where the problem lies in this approach.
I think you have a very problematic understanding of "fair".