Tom Clancy has new books coming out every year and he's been dead for over a decade. They don't hide the "ghostwriter" but they also put Tom Clancy in huge letters at the top even though he had less than nothing to do with it.
https://www.amazon.com/Clancy-Line-Demarcation-Jack-Novel-eb...
(But then why stop there, have the estate of the esteemed author go on contracting ghostwriters! Does it only work if you keep the death a secret, or would a licensed P.G. Wodehouse ghostwriter do as well today as if he were a recluse and never proclaimed dead?)
There is nothing hard about rationalizing this. If this was what "I wanted" they would just put the ghostwriters name on cover with "written in style of X" in bold letters.
But, it is not what people wanted and they would buy the book less.
But the ghostwriters are never as good as the original. Imitating style is not the same as imitating excellence. If the ghostwriter were as talented as the original author, they would be publishing their own novels under their own name, not doing anonymous gruntwork for others.
I think the distinction, for me, is that when I pay for a book I want access to the author's creative thoughts and personality, not just their particular "brand". I realize that a lot of readers don't care, especially in the YA space, but I'd rather read a worse novel from the person who conceived The Hunger Games than a perfect imitation from someone who's merely imitating the brand.