I've been watching mempool and I often see that despite the fact that there are a bunch of transactions on block with low transaction fees and overall fee becomes lower, someone comes out of nowhere and sends transaction with 10 times, 20 times, 50 times more fees than recommended. Then other people join them and overall our transaction fees get higher. One could say that it's because of old software but these transactions come from SegWit addresses.
Idk, there is no logical explanation.
I've spoken about this before too:
https://bt.irlbtc.com/view/5346270.msg57336047#msg57336047The explanation is that lots of people just blindly accept the fee that their chosen wallet or website tells them, and that the vast majority of wallets and websites are absolutely awful at suggesting an appropriate fee. As you say, all it takes is one exchange to kick start the process by dumping a bunch of overpaying transactions in the mempool, and then 90% of wallets and websites out there start matching those exorbitant fees, and we get in to a vicious cycle. If everyone (exchanges included) actually just paid attention to the fee they are paying, then everyone could save 90% on all their fees, all the time.
Replace-by-Fee is chosen by a software wallet default if I am right.
Some wallets do not support it. Which was kind of my point - if he is using wallet software which does not support RBF, then time to find better wallet software.
Without that opt-in, the only option left is Child-Pay-For-Parents which is more complicated than RBF.
And also more expensive.