I think Johns just has a lot on his plate. He's still involved in the tv and streaming side of things, right? And.....maybe still the movies? Or did he leave those completely?
Those are all things that certainly take priority over comics. A lot more money involved and you can't fudge the deadlines as easily.
I feel like if something had happened to him in his personal life, like a death in the family or a illness, someone would've made a statement about it.