[uberiosthrow]

As someone who was there, a rewrite was necessary, and with hindsight we should of done it with objective-c. The original obj-c app was built with under 10 iOS engineers in mind, and now Uber had 100s of mobile engineers work on one app in some form or another.

We didn't do a simple build scalability test until we were well into the project. If we did it would of revealed swift's build problems to us. Our swift experience is what slowed down our kotlin migration significantly. Today Uber android is still a majority Java app.

Even very recently the experience of working in swift compared to the old obj-c code base isn't as good. To this day there are debugger issues, xcode responsiveness issues and a slower build time.

Hiring on the other hand would be harder now, because it's getting hard to find people who know Objective-C and it's surface ugliness scares new people away. Swift is a decent language if you don't have to have a very large code base, so most people rightfully so don't have that much Objective-C, and if you were to work in Obj-C, you might as well go work at Facebook then.