At the time of writing, it has now been more than four years since Skin Game was released in 2014. Prior to this, the longest gap between two Dresden novels was only two years between Cold Days and Skin Game. Prior to that, there was a new book every year, from 2000-2012 and there were even two books released in 2001.
What has changed? At this point, it's even been three years since any JB novel has been released at all (Aeronaut's Windlass). Only short stories. Brief Cases was a nice appetizer, but in no way filing. It's not that Jim is now suddenly trying to take on two series at once because he's already done that while managing to still get at least one book out per year from both the Dresden Files and Codex Alera from 2004-2008.
Is it just that Jim has reached a certain amount of success and doesn't feel he needs to generate as much book income any more or what is the deal?
It's pretty alarming to see one of our favorite authors go from such a steadfast and reliable crafter of stories on a regular basis to trending toward the new GRRM track of authoring one, maybe two, core books from his most popular series per decade.
It's also incredibly frustrating to seek updates about the series from the author's personal website and be offered no other details than a now 3-year old update that says Jim is back to writing Peace Talks after finishing the Aeronaut's Windlass and that "It’s still way too early for blurbs, preorders, release dates, and the like." No, the time that was way too early for that stuff was 2015. The time for that stuff was in 2016. It's now 2018. At this point, you're basically two years late on all that preamble stuff and at least a year late on actually delivering the book.