Some of the sharpest engineers I knew built tools and business processes at startups and watched them fail as they scale. I ran an internal presentation for years at a Unicorn where I was an early employee called "Failure at Scale" where I tried to capture lessons of huge incidents we had that were caused by us crossing scaling thresholds. Eventually the presentations stopped being meaningful because the company became too big and too removed from its origins.

No but it usually doesn’t mean achieving stability at tens of thousands of users a day (or hour) and ensuring that stability while rolling out new features, migrating infrastructure etc

You definitely do. Do you think Anthropic isn't working with thousands of users an hour? They're struggling to keep up with the scale and their ability to create a stable platform is, well, existential for them. Do you think Anthropic isn't a startup? The pace of their feature rollouts is exponential.

Even in areas where startups aren't literally creating new product categories like the foundational model providers, the edge of a startup over a more established business is the speed at which they can provide value. What's the point of buying CoolCo when you can go with L&M Inc. that has thousands of headcount working on your feature. The value prop of CoolCo is that CoolCo can roll out a feature in the time it takes L&M to make a detailed specification and a quarterly planning doc breaking down the roadmap and the order of feature implementation.