Why has the kill threshold become popular? Doesn't every country have its own kill threshold?

In the domestic context, it's like: unemployed at 35, then randomly starting businesses after losing a job, wife being a full-time housewife, kids forced into international schools...

In an era of economic downturn, protecting your money is more important than anything else.

PS. Speaking of the kill threshold, it makes me nostalgic for the days of playing Hearthstone's Arena mode with slave battles.