It's a genre that spans multiple media. 

It's pretty popular.

It's not correct to say that the average Ailori is obsessed with Isekai and spends their life training for that sort of scenario...

...because that really only describes people on the competitive Isekai circuit. The average Ailori is just vaguely aware that they ought to be able to rebuild civilization with their local wiki backup and pocket omnishears. In theory.

Of course, like any other genre it has tropes. 

Tropes like getting hit by a truck.

Which neatly ties up a lot of loose ends like "why is no one back home looking for me" and "how did I get here?"

This trope might be confusing to a visitor to Ailor, who would think that trucks are approximately not a thing that exists. It's a standard suspension of disbelief for natives, many of whom do in fact think that trucks are approximately not a thing that exists.

This is a misconception. While airships, bicycles, and trains are the dominant form of transportation other vehicles exist! These are specialty- often construction- vehicles. Bulldozers and back hoes and  sod layers and so on. 

But why not something more commonly dangerous?

The most dangerous routine activity is, actually...

Stop. This needs context.

It's a conceit in the competitive game ecosystem that everything occupies a shared fictional universe. 

Not just the spaceship fighting game and the giant robot fighting game. Not just the children's card games played for the fate of the world. Not even just such conflicting genres as first person shooters and wizard duels. Even some of the popular physical sports like jousting, fencing, paintball, thievery, and of course professional Isekai. 

So we need to talk about the Double Finger riots.

A lot of gaming clans play more than one game. 

In particular, Double Finger was in a clan competing for the top of the FPS and the spaceship game rankings. 

And at the start of one fateful tournament season a rival clan came up with a plan no one had imagined before.

An awful plan!
They got a wonderful, awful plan!

So they lined up their ships like never before! Arrayed them in secret, arrayed them in force! Locked on to their target and set their course!

And they destroyed the transport ship that, in game, was taking Double Finger to the tournament. 

If that had been all, it would have been outrageous. 

But transport ships don't carry just one person.

And this one wasn't carrying just players for that one clan or even that one tournament game.

A whole new genre of in-game war crime was invented that day.