> strapping on types to eternity.

You can write TS that way. Most people who write a lot of typescript don't though. Instead of describing JavaScript's inherent limitlessness, you can deliberately reduce the size of the infinity within any given context.

Your app just knows what values it's going to get out of a function. Your IDE happily suggests the exact right set of property names to make a function work right.

You're not really working alone because you're going to be integrating with external libraries and APIs. Many of them include typescript support because it takes the guesswork out of working with them.