Just like humans, not every beast could fully develop its potential. Most creatures would only repeat what their ancestors had done, following the guidance of their bloodline, environment, and others day after day, year after year.
When humans were controlled by their instincts and subconscious, they would usually stop trying new things or innovating. As a result, they lost the possibility of discovering that they were better at certain aspects.
Whether it was humans or beasts, most of them would choose their path of development from the few options they were currently in contact with. For example, 99% of the humans on the Blue Planet were Beastmasters. Even if their talents as Beastmasters weren't that great, most of them were still walking towards the same goal.
