You may however notice that your existence might be cut short if you don't have access to food, shelter, medical treatments, because "the system" eventually has no incentive to provide for you anymore, because your labor is now worthless to capital.

Most people's existence are very strongly tied to their job. Not being able to pay basic utilities and food just the first examples.

Obviously, nobody is going to blip out of existence when their layoff notice is signed, everyone knows this and nobody claimed that. If you stepped down from your philosophical post humanist highchair a bit, you would realize that.

well i brought up the system for a reason, human existence is relative to the system in which humans exist. are there any examples of humans being systematically supported when their class of labor ceased to exist on a widespread scale? if so, did those supportive aspects spontaneously manifest? all in all, would such insights apply to a more widespread scenario, where the affected labor classes are all those involving human computer interaction?

You do cease to exist once you don't get access to food, water or health care long enough.

Think just a little past the most direct consequence - let me rephrase GP's question: What reason would the ownership class have to provide these necessities to workers when they no longer require their work?

Presumably the stress one endures when their way of life is challenged significantly is life changing. Not that you’d care though, by the sounds of it.