> And how do you predict with certainty your "highest expected load"? And if you're in a space like ecommerce, where you have 1 week out of the year with x10 or x50 the load, I doubt it would actually be cheaper than using autoscaling.

If you know when that week is, where's the problem in spinning up extra capacity just for that period, a week in advance?

Retailers, whether online or not, know with a very high confidence what their expected load is going to be a week from now.