Mike, you're making "it worked before, and thus it will work in future" kind of an argument.

It is an extremely shitty kind of an argument. And it can be used to justify any kind of bullshit.

E.g. any scamcoin which haven't yet collapsed will work forever.

As I mentioned, it depends on scale. Highly sophisticated attacks are only feasible when scale is sufficiently big.

I.e. when you have millions of dollars transacted each day it is one thing, but if you process billions of dollars, it becomes a whole another matter.

The best way to profit from zero-confirmation payment disruption is through derivatives: short-sell Bitcoin while performing this attack. But this kind of an attack depends on a number of conditions:

1. highly liquid and reliable derivative market

2. sufficiently stable exchange rate

3. significant attack impact: lots of merchants relying on zero-confirmation payments, and lots of customers paying this way

4. significant amounts of capital available to the attacker

These conditions are not yet met, and were never met in the Bitcoin's history so far.

This is why I wrote "5 years from now", I believe that we might reach those conditions around that time.

Direct impact of an attack might actually be low (but even if it is just 0.1%, 0.1% of 1 billion is 10 million, which isn't bad), but attacker might profit from the panic it causes.

Note that I'm talking about situation where Bitcoin-aware PoS solutions are deployed on a big scale, so cost of upgrade might be huge.

So anyway, in my opinion, it is actually great that Bitcoin is still relatively small: we have an opportunity to analyze and improve things.

But you seem to be hostile to people who do that (and who do not share your opinion), which is kinda uncool.

Also, you do not bother to back your intuition with rigorous reasoning, while also attacking people who offer alternatives with non-rigorous slipper-slope kind of arguments. Which is doubly uncool.