That's the nature of a textbook though, not the field.

Most textbooks present a pretty definitive take on a topic, if only for pedagogical reasons. You might get a few well-defined controversies, like various theories of matter in chemistry, or frequentist vs. Bayesians in a stats book. Even there though, that debate is often resolved, one way or the other, by the end of the first chapter.

The actual back-and-forth in most fields happens in journal articles and conference presentations instead.