That is some very specific criticism to level with pretty limited evidence. Stripe might be building their own type system, as is Ruby 3.0, but plenty of apps much larger than your provided number operate perfectly.
For the record, I do think typing solves real problems for Ruby. Speaking in terms of pure productivity, it will be helpful to bring in developers who just are not experienced at working without a type system. The downside is I think most of those problems are primarily generated by inexperienced Ruby developers writing non-expressive code. Working on large code bases with Ruby is a very strange and awesome skill. The way you name things and build standards around methods/class creation ends up being a huge positive IMO.
For the record, I do think typing solves real problems for Ruby. Speaking in terms of pure productivity, it will be helpful to bring in developers who just are not experienced at working without a type system. The downside is I think most of those problems are primarily generated by inexperienced Ruby developers writing non-expressive code. Working on large code bases with Ruby is a very strange and awesome skill. The way you name things and build standards around methods/class creation ends up being a huge positive IMO.