Well, what one could argue is that “Tetris isn’t number one” was the untenable position, and “capitalism has sold more overall” was the irrefutable one.

Oh well, the 2 fallacies are very similar with a big overlap, but if I may summarize it down to the point that I find most important:

If someone is proven wrong and they don’t take full responsibility for that (e.g. by trying to quickly push the discussion somewhere else where they’re not wrong), talking to them won’t lead you to the truth.

For anybody else reading this, this fallacy is called “moving the goalpost”.

One could also argue for “motte and bailey”, but that’s less clear.

Yeah, I just assumed English isn’t their first language? But that’s hardly the point

Can’t prove a negative, but a cost benefit analysis says it’s set unlikely. Think of what you need:

• big enough so your victim can’t hold onto the edge
• well engineered mechanism - quick, but also able to carry a (potentially fat) person
• well hidden, e.g. fine working of the edges. Or a carpet over it, but that’s additional work to make sure it doesn’t get stuck anywhere. And then carpets are your “ammo”, and the type of people to have this probably aren’t gonna have a cheapass ikea rug in their personal office.
• the whole structure of the building, below that office, needs to accommodate that functionality.
• And what even happens at the end? Is it so deep they die from fall damage? That means it needs to be tall enough. Are there spikes at the bottom? That’s a mess to clean up.
• And forget about non-lethal because then word is gonna get out and it’s just gonna become real awkward.
• Speaking of cleaning up, one way or the other there’s a body in your house now. If you need henchmen to clean that up anyway, they could just do the killing directly.

Those are all not unsolvable issues, but they all make it more expensive. And what’s the benefit that justifies that cost?

You’d get bored of the novelty long before you kill the amount of people that justifies the expense.

Those devices are smartphones. Easier to track, too.

It’s why I always go for vanilla the first time at an ice cream place.