Assuming C5 reserved instances, 5000 of those nodes is: $3 * 24 * 365 * 5000 * .5 (reserved discount) or $68M a year per aws region and 72 * 5000 or 360k cores.

Assuming C5 reserved instances, 5000 of those nodes is: $3 * 24 * 365 * 5000 * .5 (reserved discount) or $68M a year per aws region and 72 * 5000 or 360k cores. That is pretty scalable.