Catalyst question

The first 2 books (aside from the prequel) all have Audible versions available. This is a HUGE series AND Book 4 is now out and about and yet there is NO Audible version available for this book. I am limited to audio books because of focus issues primarily (surprisingly I know some people have focus issues with audio versions of books) and am waiting to start the series until it is shown that this one (book 3) has an Audible (or other audio copy) available so I know that book 4 will follow suit. I WILL nonetheless get around to reading the first 2 on Audible (own them already). Just waiting a while till the 3rd book comes out as such and I feel more confident I won't simply get caught half-way into a series and be stuck there. The narrator needn't even be Meghan Wolf or even anyone all that amazing. Just someone to audibly present the book even in relative monotone if that's all the publisher can afford. But with the sales thus far I am CERTAIN an Audible copy would sell well enough to make it worthwhile. It IS a VERY popular series!! C'mon... Thanks in advance!! Namaste!!