Board Thread:Episode Discussions/@comment-25319479-20170531105724/@comment-734582-20170603224411

Lorenzo.r.1st wrote: then why didn't kaguya awaken it, of all people? Because she already had that power, just not in her eyes. Same way she had Hagoromo's power, just not in that particular form.

Tenseigan is essentially a SPSM eye, though slightly more advanced. Kaguya already had such power over nature, making Tenseigan redundant.