but the simple fact of the matter is that most office-based employers don’t own any commercial real estate
That's not a fact. The reality is that all these rich assholes are friends with each other. The owner of the business is friends with the owner of the building and friends with the owner of the vendors and friends with the owner of the retailers. They all go on camping trips and to each other's kids weddings.
The owner of the business renting the office space might not literally own the building, but they're all friends.
Yes, and that's a problem in the US. Other countries are much better about it, and we need to change to catch up to best practices for worker's rights!