As the average difficulty goes up, pools tend to run mining software that have a predictable reorg policy, in order to minimize the probability that their own blocks get invalidated. That is why we don't see large reorgs these past few years.
Could you elaborate on this? What is a reorg policy, and are there unpredictable variants?
I would have guessed that the decline in reorg frequency and depth is the result of lower miner inter-latency.
And fewer pools.
And also more efficient broadcasting protocol, such as compact block.
And there is this option where you can turn off RBF, the receiver sees the RBF is turned off for a transaction and would accept it even with zero confirm.
If you're selling digital goods and services, where you don't lose much if someone gets a free access, and it can't be resold for profit, I think you're fine to accept 0 confirmations.
It's mostly only if you were selling gold or currency that you'd need multiple confirmations.
These days are over though. Full RBF is available on Bitcoin Core (even though not enabled by default[1]), although there's plan to make it enabled by default on the future. Peter Todd also launch bounty[2] which give miner incentive to support full RBF.
[1]
https://bitcoincore.org/en/releases/24.0.1/[2]
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2022-November/021143.html