How can they lose money at the prices they charge? They already had all the expertise to run data centers and build infrastructure. I get that there's development effort, but how can you bleed billions annually over years? Or do they discount that heavily for large customers?

I believe Cloud is an investor's playground at this point, given the huge opportunity that it presents. The fact that AWS makes a profit is due to its market position, which IBM Cloud, Oracle, Azure, and GCP have been chipping away at steadily, even if slowly. For GCP and AWS, I believe missing out on GitHub was a big mistake. Though, I fully expect GCP to loosen the purse strings for similar companies in the near future, esp given Azure/Microsoft have been on a tear of late.