This is a great presentation/article, thank you for posting it since I haven't seen it go by elsewhere.
What holds me, personally, from Sorbet is the fact that it tries (unwillingly) to dictate which features of Ruby are "bad" by not supporting them - specifically, "prepend" and Refinements. Now, Refinements I havent' seen used in the wild, but "prepend" I use the living hell of - both when designing modules and when overriding other libraries (with moderation, and when I do it is gawddam' well necessary).
While I can appreciate opinions, I am not really motivated to adopt a tool which snaps me on the fingers because I use the tools I know the utility of. I am not working at Stripe nor at Shop :-) Another thing I could really appreciate would be ad-hoc interfaces a-la Go - and more support for duck-typing in general. Maybe I missed this in Sorbet, but it seemed the idea was to "inherit like you are told to and shut up" - which is not how truly great things can get done in Ruby, at least in my experience.
Interesting to see where Sorbet goes in the coming years - and stoked for more RBS/Sorbet interplay!
I was impressed at recent changes in the Sorbet syntax but also with the proposal that we make code comments available to the ruby VM.
That would allow Sorbet to adopt the rbs-inline comment syntax for both runtime checks and static analysis.
So there does appear to be a way forward on this, which is pretty exciting.
1. https://blog.jez.io/history-of-sorbet-syntax/