CGC’s TAT’s are due to getting more books in compared to how many they can process. Simple math.
If they can grade and encapsulate 2,000 books a day, yet they get in 4,000 books they go backwards another day despite working hard. Doesn’t matter if those book come in orders of a 100 books or a single book. Every book sent in that surpasses what they can get done in a day sets them back. The further behind they get, the greater the cascade.
To think they are where they are due to the actual size of certain submissions is laughable. CGC has always received large submissions in the past. What has changed is everyone now knows they can make a buck or two in the comic market and the sheer number of submitters has increased greatly. Once people find the next get rich quick scheme, they will focus their monies elsewhere, which will lessen the backlog. ATM that shows no signs of slowing down.