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.
What will get us here in the US first? Exploits discovered to banking infrastructure that can't be patched? A new virus or ransomware that AVs and firewalls can't be updated to stop? Navigation software for satellites and boats not being able to be updated to deal with ever changing environments stopping trade world wide? All our medical data going poof because an auto purge feature of old data forgets how to count?
Who knows! Tomorrow may look the same as today, 3 weeks from now might look about the same, but sooner or later we'll basically all be running windows XP.