In recent years, Crown Castle has been the most aggressive of the three major US towercos about expanding its business beyond macro towers and rooftops and into small cells, fiber xHaul and edge computing – all of which will, together, be increasingly important to enable new dense and virtualized 5G RAN and core architectures. Its major rivals, American Tower and SBA Communications, were more cautious, focusing on expansion through new geographies, but they too have recently focused on the potential to add data center and small cell infrastructure to their neutral host portfolios. During SBA’s third quarter earnings call last week, executives were heavily focused on the temporary boom that is coming from AT&T’s and Verizon’s rapid build-outs of their…