> We're all assuming content comes in constantly, but that's not the case. I imagine they spike heavily at peak times, perhaps 5-6 fold (judging by my own site statistics). Serverless might be good for them because they can handle small loads with small costs and large loads with no effort.

No. I've pushed 1000 r/s (approx) on a price tracking tool at work for keeping track of competitors on one of those boxes. Their largest spike (even if you assume its 10x their average) would be at most 15% of that.