Funnily enough, I think it was the fire risk that caused them to ditch the idea and move to their current design. Though I know modular design is highly likely to be used by all players as edge nodes spring up worldwide.

It was also that the container had literally no advantages. It was just a meme that did not survive rational analysis. The building in which the datacenter is located is the simplest, cheapest part of the design. Dividing it up into a bunch of inconveniently-sized rectangles solves nothing.