I wouldn't necessarily agree with that. It depends on scale and the skills available to you. Yes, amazon and co do a good job of pushing down cloud costs, but you still need people to manage these services.

Also it depends WHEN you build things. Redshift for example is now pretty viable and potentially more cost effective than what Etsy does. 2-3 years ago that very likely wasn't the case.

I'm not saying Etsy doesn't have somewhat higher system costs than others but I doubt it's the cause of their issues.