It's a shared responsibility.

It's true that routing is a big cause of the problem, and people in certain areas or with certain ISPs have more of an issue than others. That is part of the equation, and it's on the ISPs of various functionality.

There is also a huge number of games out there which don't have this problem for the same exact people, many of which require the same or stricter timing as part of their mechanics. That is part of the equation which is firmly on SE, either for their programming or their network infrastructure.