Are there any people who really think the world will come to an end?



Yeah, there are those types.

The world technically will not end until either a very large asteroid (most likely a planetoid, look into how the moon was created) slams into it or in the next 5 billion years when our sun burns out and goes nova engulfing the majority of the inner planets.

As for human mass die offs, then that is entirely possible. It has happened before, just look into the human bottleneck where humanity was reduced down to 1,000 or so mating pairs. Pole-shifts have happened and will happen again. Catastrophic volcanic eruptions have happened and will happen again (super volcano size, such as Yellowstone).

Pick your poison is more like it. Just because Humans are here does not mean that things will magically stop for us. The universe and planet will continue doing their thing as if we were never here and that is a fact of life.

There are also human related scenarios, all caused by us such as financial collapse which will lead to mass civil unrest/disorder ushering in an age of anarchy rule. We have a human created problem of food and resource scarcity that may also cause social collapse. We have social engineering which may also tear us apart as self centered greed causes humans to lust after more and more which can cause social upheaval.

Personally, my motto is hope for the best but prepare for the worst. Things have happened and WILL eventually happen. There may be a lot of warnings or it may just go BOOM! without any sort of warning.

Just my perspective on things.