We're using it (300 engineers, 50k .rb files). It sucks, like everything else related to Ruby. It's ugly and hard to read. It would be better to use a real language that has types built in.

When you're hacking together an MVP as quickly as possible, it may seem like a brilliant idea to not have types. Then you have a real company and a larger team and you find out that not having types causes lots of problems. Then you graft an ugly hack like Sorbet onto your code base. It's more work and more error-prone than having a real language with types.

The official Ruby motto should be "penny-wise, pound foolish". Everything about the language is a disadvantage when you have a large code base.