You would need the inheritee and the engineer to both be willing to commit murder and run the calculus that the money is more valuable than the risk of them going to jail and losing their inheritance forever, which is probably a really bad bet given one of them is a spacex engineer or something and the other is, what, an heir to the bezos fortune?
Most heirs are not going to attempt to murder for the money. They normally are already enjoying that wealth. And if the money maker stays alive it just grows even more.
Now even if they have a motive. How are they going to connect to the right engineer? They likely don't have the skills to even identify an employee that could deliberately sabotage the system.
And you likely couldn't do it with just one employee. There's at least one other person reviewing their work. And tons of inspections and tests you'd have to hide it all from. So you'd end up with a heist movie.
That said, the groups that could do things like this are state actors. But then we are talking about a very well funded group that can afford to spend years placing people in key positions. And then we get back to motive. Only state actor that would really want to hold back SpaceX or Blue Origin would be China. But the reaction from such sabotage could go a lot of ways. Not worth the resources.
We just got our asses kicked by Syria and, more recently, the Taliban. Even our idiot generals aren't eager for more of that. They'll be able to justify several trillion dollars more in "defense" spending before needing to incite another war. Expect the next freedom-haters to be a somewhat smaller nation, like Grenada.
Silly