I've worked at a dozen startups. Some successful made me a lot of money, most failed miserably.

none of them failed because we didn't scale the tech, or use the wrong language or a bad DB schema or whatever. It was always market fit, constant pivoting, lack of product focus, etc.

And I'm not saying "it's never the engineers' fault". Engineers should worry about stuff like that, but we spend way too long focusing on stupid things like the language or the DB engine we use.