Ask your parents or grandparents how expensive long distance or international calls used to be (and still are for landlines). It was dollars per minute, wholly untethered from actual costs.
That's what South Korea is doing here and it's a terrible idea
Look how cheap service can be in countries where it's cheap, then look at the USA/Canada. Neither of them have sender party networks pays yet they both increase network connection costs way beyond what's necessary since they have regional monopolies.
Basically why does a sender party network pays system lend itself to a monopoly, while rogers supporting entire businesses in Canada who have no alternative is not?
They don't. I have many broadband options.
This will always be an issue with SPNP. Anybody who doesn't want to pay is basically removed from the internet for customers of the ISP.
It gets even worse when ISPs own competitors to the senders service. Comcast owns Peacock; think about what relative subscription prices would be if they could charge Netflix for access to your connection, but Peacock gets it for free (even if they are required to pay, they are paying it to themselves).
For example, in America, it is taken for granted that you pay for both incoming and outgoing calls. Koreans, on the other hand, would find it preposterous. Why should the callee pay, when the caller is already paying for those minutes? It's the same situation, but reversed.
Would be entirely logical and sensible model.
The complaint is that ISPs are charging both sides. Hence the pro "net neutrality" position.
(Aside: "Net neutrality" is a terrible phrase. Obscures rather than illuminates the policy debate.)