Actually not entirely correct. The battle of Macragge puts lie to the Tyranids always keep coming. Of course Macragge was an exceptional battle and the Space marines managed to pull off some serious major victories, including destroying the fleet using the Dominus Astra. Once the local Norn Queens were killed off, the Tyranids were just slightly easier to remove than Orks. The only hope Star Trek would have is biologic weapons, fast acting biologic weapons. Star Wars would at least stand a chance with the use of Death Stars, Galaxy Guns, Eclipse class Star Destroeyrs, and of course the Sun crusher.