Processor architectures maybe. They put Rust into Debian and it's so bad that now e.g. amd64 is ruined forever for any OS and won't see any new processors in the future. We'll have to move to a different architecture. I didn't watch the video since I treasure my brain cells too much but that's what I choose to read into it.

(A more reasonable reading is that Debian now ships a kernel that includes Rust code and coincidentally has also dropped builds for several obscure architectures but I do not feel obliged to assume reason with a title and thumbnail like that.)