How to save 1M off your cloud infra? Start from a 2M bill. That's how I see most of these projects. You create a massively expensive infra because webscale, then 3 years down the road you (or someone else) gets to rebuild it 10x cheaper. You get to write two blog posts, one for using $tech and one for migrating off $tech. A line in the cv and a promotion. But kudos for them for managing to stop the snowball and actua…
They saved $100k in the move or 2% of their engineering costs. And they're still very much on the cloud.
If you tell most organizations that they need to change everything to save 2% they'll tell you to go away. This place benefited because their previous system was badly designed and not because it's cloud.