I have not yet seen a single cryptocurrency that hasn't resorted to dev intervention under circumstances of bloat/flood attack. Whether it is about fees or block size, something has to give in order to stop it or restrain it.
Which flood attack? The couple of "stress tests" that we had last year?
The network is in constant saturation by dust and spam that want to be processed for free or near zero cost. A stress test is just a more focused version of the same issue.
Near-zero to zero fee txs equals near-zero to zero fee attacks. Attacks which do not have serious economic disincentives betray a broken underlying game theory.
If that's a problem, a minimum fee should be introduced.
It is a problem but we also face political pressure. You can get crucified for doing the right fee with populist bullshit like "ohhh the devs are raising the fees, they want to make BTC expensive for users" crap.
If I look at the last eight blocks (395,151-395,158) I see that 16,093 tx were processed for a fee of 3.08 BTC. That's 0.000191 BTC/tx or USD 0.0766 . I'm not sure how much zero-fee transactions are in there, but with an average of 7.7 cents, how much higher should the minimum fee bee in your opinion?
Free or nearly free txs = free or nearly free abuse. If you allow that = you are a joke coin that can be attacked by script-kiddies.
In BTC the last line of defense, in absence of serious fees requirement, is the block size.
[...]
I was thinking that an ideal way to eliminate spam would be for the miners/nodes to agree to not process txs that use a fee lower than 10 cents. We'd probably go down to 200-600kb blocks right away (depending the load) with plenty of room to spare - and probably everything would go in in the first block. But having prices in USD doesn't work in terms of code (which deals with BTC fractions).
10 cents is a lot, I think. But apparently 7.7 is already the average, so there's little in between.
One thing I don't understand. If big blocks are such an issue for Chinese miners, why don't they refuse to include tx with too low a fee?