I think editorial believed they had a good thing with Ben Reilly - Scarlet Spider. They had a beloved character that a vocal fan-base had been desperate to return for over a decade, they had a safe creative team (Peter David and Mark Bagley), Ben was coming off a huge cross-over and they already had the end-point of Spider-Geddon in mind.
I think the main problem was that the book didn't give anyone what they wanted.
Original Ben fans wanted that version, maybe even his original supporting cast. They wanted to see the evolution of what Ben could do now after so long away, how he reacts to the new world, how he could interact with Kaine and MJ and May (who he thought was dead). They wanted to see the mistakes of the Clone Conspiracy dealt with and for classic Ben to return.
Newer Ben fans wanted to see the aftermath of the Clone Conspiracy, is he still a villain? Would he try again? Has he seen the error of his ways and will try to be better? Would he interact with the surviving clones?
Mostly, I think we all wanted to see him interact with Peter and a get resolution/closure to the Clone Conspiracy (which ended without Peter and Ben concluding their feud).
But we didn't get any of that.
Instead we got a strange new setup with an unlikable, occasionally crazy Ben (characterised very differently from either classic Ben or Clone Conspiracy Ben). A weird Vegas setting where his motivation is kind of trying to save a little girl whose mother is a mob boss, also very unlikable, but also he sometimes fights crime. We get a returning Kaine, whose motivation is to kill Ben except when he changes his mind. And then Death came along (never a good sign) and his aim is maybe to save his own soul, which he couldn't do selfishly. It was muddled, unfocused and mostly unlikable. Heck, the original intention was even to change Ben's iconic hoodie costume.
Here's Ben in a holding pattern, Kaine in a holding pattern. No New York, no original supporting cast and no Peter - all of which I suspect was editorial decision with Spider-Geddon on the horizon.
But for now Ben's gone and won't be getting another book anytime soon. Kaine is gone as a result of Ben's book. And I can't see a Spider-man editor commissioning a new book anytime soon, as the last one failed.
I don't think they've learned a lesson, as I don't believe they know why the last book failed or it would have been changed - or perhaps it simply isn't a concern. They had a release window for the book (X-number of Spider-books per month), they wanted to keep Peter David on a monthly, it sold moderately well and was ultimately disposable because of Spider-Geddon.
Hopefully, Spencer (or the next writer) will bring Ben and Kaine back to New York and make something of these characters.
Also, Diet Spider-man is hilarious but doesn't really give me hope that Spencer wants to show Ben any love.