C# has a ton going for it:

- modern, cohesive language (strong static typing, functional features, first-class async/await, value types, spans, stackalloc)

- pragmatic, not ideological

- great runtime (.NET CLR) that is cross-platform (Windows, macOS, Linux)

- can do native compilation

- one of the best developer experience (IDE, compiler, profiling)

- excellent for many domains (cloud/backend, desktop, mobile, game dev, data & ML, systems adjacent)

- language scales well with teams and code base size

- great performance / safety balance

- native interop

> C# earned this distinction by achieving the largest year-over-year increase in ranking.

And C is in second place in terms of year-over-year increase (besides also being second place in absolute ranking, after Python). Go figure.

> I always assumed Java would eventually prevail

I can understand that from an ecosystem perspective (at least to a degree), but based on language merits alone? Hard nope.