TypeScript seems better (or at least on par) typing wise to Python.

I don't think anyone is picking Python for it's type system. It's still a second class citizen at best.

Common misconception. You have startups choosing a language while trying to absorb unsustainable operations costs to justify using the wrong language instead of picking the right language from the start.

Until 7 years down the line you have to round up a team of your most experienced engineers and add some to figure out how to scale the frecking' thing.