What to do about the next book

It's been over a month since the last post.  The reason for this is simple: I've been writing.  The bad news is that I haven't been writing the book I should have been writing.
I'm sorry!  I know most of my readers enjoy my historical fiction.  I enjoy researching it and I've loved writing it, but for the past few years I seem to have been running into the sand, and I finally got irretrievably stuck.
Perhaps it was a mistake to change period?  My training is as a classicist, and that is still the period I love most.  I did feel, though, that I was getting stale, recycling some of the same material from book to book, and that I needed to challenge my brain with a completely different period--hence the English Civil War.  I did like my two Civil War novels, but I don't think they're as good as the best of my classical books.  On the other hand, I don't feel my last few classical books were as good as my best, either, which is why I made the change in the first place.
I should spell this out: I have always done my very best with every book I've written.  When a book is not as good, this isn't because I've cut corners or failed to invest the time and energy it needed: it's because I was unable to make it any better.  Sometimes there were structural elements pulling in different directions, sometimes I couldn't get the plot quite right, sometimes the lightning just failed to strike where it was needed--but the failures have never been down to will and commitment.  If any readers have been disappointed, I can only apologize and say that I did the best I could.
My last published book, A Corruptible Crown was particularly demotivating: the publishers cut it by ten percent to save printing costs.  Now, I don't think my words are holy writ; in fact, I believe that most books, including mine, benefit from cutting.  In the past I've been happy to cut: Dark North is only about three fifths of its original length.  A Corruptible Crown , however, was not a fat book--it was quite pared down to begin with--and my publishers weren't pretending that the cuts they made were to improve the novel: they were made explicitly to save money.  I suppose even so about 30% of what they did improved the book and another 20 or 30% was neutral.  That did leave, however, 40 or 50% of the cuts being into red meat--things which were in the book for a good reason, and which caused damage when they were taken out.  I know that they, like all publishers, are struggling with the harsh economics of printing in an increasingly digital world--but for me this was, as I said, extraordinarily demotivating.  Why should I sweat and struggle to make a book as good as I possibly can, if the publishers are willing to cut it to a Not-what-it-should-have-been?
My first response to this was to e-publish a couple of fantasies that I'd written to unwind, liked a lot, but failed to sell.  (No printing costs!  I can put in as much or as little as I like!)  They earned very little, but the books got more stars and more reviews than the printed ones.  I still didn't feel like tackling the next historical, so I wrote a couple more.  Then I started another historical, intended to finish off the 17th C. themes I'd dealt with in the two civil war novels.  I did a lot of research, embarked on it--and got stuck on chapter two.  I then wrote nothing for about a year--which was unprecedented for me, and depressing.
Now, as I said, I'm deep in another novel and happy as a cow in clover--except, as I said, it's not a book I should be writing, it's another bloody fantasy, and probably destined to go straight to Kindle.  It's different from the last ones, it lets me play around with different viewpoints and some fun ideas--but it's not what I wanted to write or what my small band of followers wanted to read.
So, if you're a member of that small but elite band--I'm sorry!  Maybe after this I'll be able to do a proper book again.