Do the traditional techniques of protection still work in the age of work from home? Yes, but you need to use different rules and products. Traditional networks have been set up in the same fashion: a traditional Active Directory domain, a variety of domain controllers, workstations under the control of that domain, and all tucked behind a firewall.
Before the pandemic we had roaming laptops or users that gave us the headaches of user profiles and group policies targeted to those who stayed in the network versus those who roamed our domains. The pandemic hit and our workstations are now anywhere and everywhere. Instead of a somewhat nice and tidy domain tucked behind a series of firewalls and defenses, it is now connected to the same network as Alexa devices. The response is often to throw scanning engines and antivirus products at workstations, but all that does is delay boot up times and logging into the network.