Everyone with your exact job title in your industry vanishes, how long until awful things happen?
I'm a support engineer for dental software. So difficult issues won't get immediate resolutions, and instead development will actually have to fix things because offices will be crying at them for a fix instead of at me.
Admin paper pushers coordinate so others can have frictionless meetings. Most likely all meetings will be awful, and initiatives will not have approvals so fraud will propagate quickly
You say this as a joke, but it will not be business as usual. Trust is HUGE when it comes to investments. Without admin, trust goes down, investors become misers, total wealth decreases, and everyone will have the same credibility as a scammer on the phone talking about Nigerian princes etc. So it may not go to a barter economy, but several parts will stagnate because they can't trust investing in their own company's growth.