Instead of having Internet connectivity 24/7 for IoT devices or critical infrastructure, why not have a small window for things like updates and so on, but be p

Instead of having Internet connectivity 24/7 for IoT devices or critical infrastructure, why not have a small window for things like updates and so on, but be physically air-gapped the rest of the time? The window doesn't have to be at the exact same time either: if you need 20 minutes to download and apply updates once a week, then you can start that 20 minute interval at anytime on whichever day. The air-gapping could also be done using analog means or another network that isn't connected to the Internet. The best solution would be to be air-gapped 24/7, but in cases where that is not possible, there are other viable and more secure approaches than being online 24/7.