Trimming the book is one thing, and I agree with you 100% on both examples. Removing the conclusion in a way that completely alters the message is another.
This happened with the Heinlein book "Podkayne of Mars" -- the original ending had one character dying and another character changing course because of it. The editor thought it too heavy for a kids' book and directed a rewrite where everyone lived.
Years later a new print included both endings and staged an essay contest to decide which is the "right" ending.
I don't know if he's gotten sloppier or just more verbose, but do find his later writings to be largely plodding and much less interesting than his earlier works. He pretty much lost me with The Baroque Cycle. Those books were a chore.
But I think that has to do with the clear change in his writing style, which has diverged from my personal tastes. So it's not a judgement call on his writing either way -- we've just grown apart.
> He pretty much lost me with The Baroque Cycle. Those books were a chore.
I wouldn't call those "later writings," he's written quite a few excellent (and better) books since. Anathem, Seveneves, and Fall; or, Dodge in Hell were excellent. Termination Shock was a quick read.
I've since gone back and re-read Cryptonomicon. I don't know know if I'll redo the whole Baroque cycle, (Because it was so long,) but I do have fond memories. I suspect it's the kind of book that's better the 2nd time through.
BTW, Fall; or, Dodge in Hell ends the Baroque Cycle. Enoch Root is in that book and we figure out what he really is.
I could not get through the Baroque Cycle, and hated Fall. The only other Stephenson book I've not made it through is Anathem, which I know is a heretical position to take, but I can't help it.
And authors gaining editorial control is why so many books later in a popular author's career are worse and worse - no one able to trim them.
As examples I'll pick Neal Stephenson and J.K. Rowling. Even the fans have to notice how their work has gotten bigger and sloppier.