I think it was clear early on that Swift is the future of iOS development. But if you’ve been around long enough, you’ll have observed that it takes about 10 years for a new language and associated tooling to reach “maturity”. What “maturity” means is debatable, but one aspect is that the ecosystem grows to handle the extreme edge cases like very large scale development. And boy was Uber pushing the edges of what was possible on iOS at the time.

So by my way of thinking, they moved at least a couple years too early. (The Swift project started internally in 2010, first public release in 2014, Uber’s rewrite started in 2016.)

If they had stuck with the Swift ban they would certainly be facing a hiring problem today.