@quirk They could just hire remote scabs for all work that can be done remote and use helicopters for those that absolutely need to be on-site (likewise food delivery via private drones is doable).
There's very little we can actually do about that if they're willing to bother.
The social mechanism of sharing what they're doing and refusing to work for employers that do that would be more practical and effective. Widespread membership in the union would make it a lot easier to check for that.
@lispi314 except there may be laws in your country that require work be done in the office. Laws that may have been put in place to protect you and your rights. Laws that would be much easier to circumvent should everyone decide they ought to be working from home. And if you think it's so easy to get everyone in your profession to join your union, I recommend a book called Dreams of Dignity, workers of vision. If you want to know your future, study the past.