Maybe we read different articles? I thought the context was how it was hard to do GC in WASM currently, which is why we don't have many language choices. With that context, C# running on top of WASM seems pretty relevant?
Garbage collected languages have been running in WASM for a long time already, but they had to "bring their own garbage collector" to run in WASM, which increases the size of the WASM blob.