A couple of things here.
I disagree with your size estimate. 1500 square feet is a small house. That is a very questionable estimate for space requirements here. You might know a lot more about this than I do but I am in IT and have not seen space requirements like that for high tech networking equipment like that since the 1970s.
Here is the rack room at Sofi, a much bigger stadium with far more network requirements. You can look into it from the stadium concourse. I assume this is where all the equipment for the network is housed. This includes switches, servers, routers, etc (not just the equipment installed by the wireless carriers).
That said, I don't work with this equipment and don't know for sure. I know there are people on the board who do know this stuff for certain. I encourage them to weigh in on this. Definitely agree that with our undersized concourses, we could not entertain showcasing the world class technology used at the dome like Sofi does so well here.
The powers that be have known they were replacing the seats for years. They actually are behind on that project as well. No way this wasn't knowm were the design for the dome was made by JMA.
Also regarding space limitations, I agree that the existing rooms in the dome are all fully utilized. However, I suspect you aren't thinking about the major expansion on the eastern side of the stadium, which is adding a ton of additional space to the building (finally going outside the original footprint) and all the space above the upper level (take a look at the stairs and the space up there).
What is done is done. I am sure Pete likes having that third party equipment housed outside his facility.