I think they're talking about their own team. Cross country or cross team meetings might always require Zoom.
If you have 3 days of office, you'll always be in Zoom calls because at least some of the team members will be at home.
I'm not sure about Amazon, but in some of these large companies the team is still distributed even when they are "in-office". So everybody is still on zoom calls.
Not really. At a company the size of Amazon teams are often in other buildings, if not other cities or countries entirely. The zoom calls continue unabated.