Yikes - I looked and there are rumours from 2015 that this was the case. https://www.koreaobserver.com/lee-kun-hee-dead-alive-health-...

According to many he’s been dead since then, and his heir has just been trying to keep it all hidden because SK’s inheritance taxes could threaten the family’s majority stake in the business.

So is this the heir "buying the dip"? Staging the death at the moment in which the inheritance is likely to have the lowest market value?

In the UK if you get a (sizeable, asset) gift from someone and they die within a certain number of years you then need to pay inheritance tax on it. Could be the same mechanism here? Date has passed so turn off the ventilator or whatever?

Regardless of what you think of the conspiracy theory, they've had quite a long time to plan what they do next, so you'd presume they had something figured out.

Precisely.

It's quite amazing how some pieces of conspiracy is so readily accepted while some others are vehemently denied to the point where people are sent to jail over it.

It’s a rumour that would have been easy to disprove if he was well.

What would be the benefit of disproving such a rumour? No company is going to turn down business with Samsung either way, while a public showing that you are fit may contradict your lawyers in their (current or near future) attempts to dodge subpoenas.