This cut office costs in half and increased productivity. It was quite good.
Speaking of remote, I've worked two jobs which were semi full remote, where we'd come in if we wanted to collaborate, on average 2 days a month. Both scenarios would save the company money on office costs.
One company, we had a full dedicated office, where we'd find a space we wanted to work in. It was normally abandoned there, except the CEO, SFO, and CTO was often there every day. We'd find an empty office room and close the door having privacy. It was quite nice. The advantage of this was our office space was tiny, compared to how many people we employed. Likewise, when we wanted to come to the office the environment was always fantastic.
Another company I worked at used those shared office spaces with a pay as you go plan. Eg, if you reserve a meeting room, they charge the company for it. We'd go there and find some desks we'd like and go at it, or reserve a meeting room if we wanted. The company would pay for it, so I'm not sure the price, but the environment was good with a café and great outdoor collab spaces. I'm sure it saved the company a lot of money.
So yah, partial remote and full remote do save companies money. They increase productivity and reduce office space costs. However, both of these are quite different than shelter in place, where those who would benefit from coming into the office can't. Shelter in place is less productive and far more frustrating than proper remote.
Is that actually true? The company isn't paying people to maintain their home offices. Any day where everyone works from home is a day where they don't need to have cleaning staff, food services, etc. come in. It may seem inefficient to have the building sitting there empty, but relative to having people there (and not relative to having no building at all), it's probably a net win.
Think about how many restaurants in prime real estate locations are closed for breakfast or on Mondays.
It might be easiest to simply take turns driving to each other's house.
Plus everyone needs to still live within commuting distance to the office, and also have a productive work space at home, which is a huge luxury in a place like SF to have an extra room for an office.