Board Thread:General Discussion/@comment-27083746-20160326213304/@comment-957629-20160328191824

Reni was training in Bankai before he met Ichigo, he said he was close to achieving it when he showed up to train with Ichigo.

Ichigo only achieved it due to a cheat created by Urahara and as far as I can see, there aren't scientist Quincy around that can create quick cheats for Ichigo. Ichigo's main power are his Shinigami powers, everything else in the series is an addition to those powers.

And lets be real, considering how quickly Yhwach went for the Soul King, Ichigo doesn't have a week to train.