There are already examples of alternatives, like it could have some kind of brain and communication apparatus to work with others of its species and put together things like GPU simulations of protein modeling to generate optimized artificial antibodies.
I believe what is meant here is that the alternative is to have a highly developed capacity for abstract thought that you then use to collaborate with your species to develop antibodies in a laboratory (humans are an example of this, although we don’t rely upon this mechanism)
Yeah but how is that going to arise out of nature? It's like asking why birds use vision + magnetism to navigate when they could just use GPS -- the MVP is too massive and inflexible.