When I lived there, Phoenix was too regional--GPEC was and probably still is pretty much the G and not the P.
Secondly, Central Phoenix is a shit place to live for families. The schools are garbage and the commute is loooong from places that do have decent schools. Gilbert's are some of the best anywhere.
And as long as Gilbert or any suburb has cheap shovel ready and spec sites like Rivulon with abundant parking, corporate campus users are going to go there--I bet you dollars to donuts they're gonna go to Rivulon. I think it's rare these days for a company to open a branch office of thousands of people in a downtown tower, that's usually reserved for homegrown companies that are invested in the area and building headquarters or there's cachet for being there. Phoenix has made strides but it still has a lot of problems that don't fully outweigh the benefits of locating there. State Farm was a fluke that also depended on a land subsidy.
Finally, I just see accountancy as a stuffy industry that would work well in a bland family friendly area that would call a place like Wildflower Cafe "
quirky." I think along with Chase leaving Chase Tower we're seeing the old downtown holdouts of financial companies leaving for the suburbs. Tech and startups who keep coming downtown want to attract younger demographics and they don't mind the older stock of buildings with limited parking.