> compute is cheap

There was a whole thread yesterday about how a dude found out that it isn't: https://briananglin.me/posts/spending-5k-to-learn-how-databa... (also mentioned in the RbtB post)

Depends on the provider. I've checked the pricing of 4 top relational database cloud vendors (Google, Amazon, Azure, IBM) and they all charge for the number of CPU cores and RAM you buy, not by the number of rows scanned like PlanetScale did in the post you refer to. They'll be more expensive than buying your own server but not nearly what PlanetScale charges for full table scan queries.

When do the rest of the folks figure it out?

To a degree, this is true though. An engineer's salary is a huge expense for a startup, it's straight up cheaper to spend more on cloud and have the engineer work on the product itself. Once you're bigger, you can optimize, of course.

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If this is a case from real life that you have seen, you should definitely elaborate more on it. Otherwise, you are creating an extreme example that has no significance in the discussion, as I could create similarly ridiculous examples for the other side.

There are always costs and benefits to decisions. It seems that are you only looking at the costs and none of the benefits?

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If you're suggesting that we should double the size of the hardware rather than add a single index, then I respectfully disagree.

But your point is well-taken. Hardware is cheap.