> There hasn't been a lot of study on this topic* but what little there is shows that 3% of errors found can be mitigated with type systems, where they do not exist, fixing these classes of errors takes less time than it took to use the type system.

It seems to me like you're cherry picking evidence. Copy-pasting from a previous comment I made in another thread (https://news.ycombinator.com/item?id=19530274):

There is plenty of evidence showing that modern type systems reduce bugs considerably.

In Airbnb, they found out that 38% (!) of bugs could have been prevented by using TypeScript[1].

Another scientific study discovered that TypeScript and Flow could prevent about 15% of bugs in committed code [2]. And these aren't even measuring reduction of bugs in non-committed code!

Stripe is also writing their own type checker for Ruby and engineers have reported an increase in productivity[3].

[1]: https://news.ycombinator.com/item?id=19131272

[2]: https://blog.acolyer.org/2017/09/19/to-type-or-not-to-type-q....

[3]: https://sorbet.run/talks/StrangeLoop2018/#/