Board Thread:General Discussion/@comment-26830922-20170211043007/@comment-26830922-20170212161812

As the first page says, Yhwach was only able to obtain the souls of the opponents his Quincy fought because he was able to spread parts of his soul around the Seireitei during the first battle. To do so, he had to be physically present. However, Yhwach had been sealed away for a thousand years before the final arc, and so could not have been physically present for whenever Quincy fought Hollows in that time period. Even if he was not sealed, the number of Quincy during this time was too numerous for him to be there every time one fought a hollow.