I wonder too if we might see a world where a lot of application and business-logic code in Rust gets written essentially in the style of Python or Ruby— lots of immutability and copying stuff around because perf doesn't matter at that layer. But then the heavy processing part of the application can call down into vetted crates which do take advantage of Rust's more sophisticated features.

Am thinking here of the relationship between Python and Numpy/Pandas. Lots of companies use Numpy heavily but wouldn't dream of trying to hack on it or build such a thing themselves from scratch.

Similar story with places which do things like ban writing their own template code, but permit the use of std container classes.