So what is an example of a self-founded project that used types and is a business success now?
You get the picture.
Also, types are a spectrum. C++ has types, Objective-C has types. Those alone have enough success stories to fill tomes! But of course you’re talking about strong static type systems like Haskell, Ocaml, Scala or ML, so you should read up on Jane Street. Or Mercury. Blockchains like Cardano.
Personally I think the onus is on you to prove that types are _not_ useful. Many of us enjoy types.
Pretty much all successful indie games use typed languages. Of course, there is a mix with untyped scripts in there too. But many only depends on typed languages.