[Macha]

What of people that don't use C#? What of teams with libraries already built in Rust? Also I've been on teams building web apps in Java that were more complicated than just CRUD. We had one where the GC behaviour of Java was decidedly suboptimal as the applications would for for minute long GCs due to large in memory caches

[UltraViolence]

There are very few developers that aren't fluent in C# or Java or another C derived language. The learning curve for Rust is pretty steep, since the deterministic memory management requires new concepts to be mastered whereas with C#/Java you can just create objects left and right without having to worry about when to clean them up.

C# and Java have vastly more libraries available to them than Rust.

Having sub-optimal behavior is usually a sign of poor design IMHO. But it's difficult for me to pass judgement without seeing the application code. Also, I doubt that Rust would be of any help in this case.