This isn't news or any hint about the future. Most businesses and companies have tower presence from all the major carriers. It helps them do business. Verizon has a lot of business customers. Plenty of Apple and non-Apple folks come thru their campus, plenty with Verizon serviced devices that need full coverage.
I used to work for GE, and we had Sprint, Verizon, and AT&T towers installed, and internal antennas in each building.
Now I work for a major pharma company and we have the same.
The Apple campus would be no different in that respect.