Once egress passes a few hundred terabytes a month, the cloud bill stops being a compute bill: bandwidth priced per terabyte at cloud list rates is ten to thirty times transit, and it decides the comparison long before rack space or hardware amortisation do.

The two curves differ in slope, not just level. Cloud cost rises at the full egress price with every terabyte; colocation rises at transit price, typically an order of magnitude flatter, after paying a fixed step for racks, amortised hardware and operations. Where they cross is set entirely by that fixed step divided by the price gap.