[gngeal]

Europeans were almost wiped out by the plague

Uh, nope. What does "almost wiped out" mean to you? 30% of population dead is "almost wiped out"? It's horrible, of course, but there were still 70% who stayed alive. Well, I could say that I can jump almost three meters high with that logic. :-)

[memracom]

What if we lost 50% of the world's population?

We would be knocked back to the ... 1970s!?!?

In the 1970s the world's population was about 3.5 billion and today it is double that. Sure it would be very disruptive, but there would still be plenty of creative people around to pick up the pieces.

[cmdkeen]

There is a point where the breakdown in social order is going to lead to a much greater problem. If the food and energy systems we rely on to supply cities break down then you'll be looking at problems other than the outbreak causing deaths.

If society breaks down then you'll suddenly be looking at countries being unable to support anything close to that number of people.

[coldtea]

"Almost" means that the "30%" could easily have been 70% or even 80% were the thing any more potent.