Many people at Google still use desktop Linux workstations. Those would be airgapped too under this plan and force these people to change to another workflow. There are at least hundreds of people who have been there 10+ years still using desktops for all development. For example on the team I was previously on, 4/8 people used a desktop workstation as their main device.
I used a cloud VM as my main machine, and still used internet all the time. I used github to sync my configuration (using a proxy would be out of date and no way to push), amongst other things.