I don't completely disagree with your point, and I would not be a person to advocate Go for game development, but "wholly unsuitable" isn't true. A large number of successful games are released that depend on runtimes with similar garbage collectors. Most notably games running on the JVM and CLI. These are "real games" with real performance considerations.
See: Minecraft, Terraria, Magicka, AI War, and many more.
See: Minecraft, Terraria, Magicka, AI War, and many more.