On the other hand, increasing performance by 0.5% at their scale is big savings. Certain kinds of optimizations can save over 10% in runtime performance, easily. That means less compute, less engineering time spent optimizing with other approaches, snappier performance compared to the competition, and so on.

Yeah, pay the "business" person better who decided, wisely, to fund these kinds of projects. But in my experience, it's a lot easier to find a strategic thinker who can understand my previous paragraph than it is to find an engineer who can accomplish it. It's especially hard to find engineers who can see that opportunity, explain it well enough to get funded, and bootstrap the project until it shows enough promise to justify itself.

You're not wrong, though, that network effects and so on are a much bigger determinant in competitive advantage at a large scale. But "business strategies" can and do include ideas like "don't buy extra data centers".