What factors led to the decision to stop?
Boredom. Imminent burn-out. Creative frustration. Worries about the state of the market, and its future in the medium and long term. A desire to actually make some money.
Hogshead was set up to publish games that I designed; I was supposed to be the company's creative powerhouse. I had no idea that running a small business is so incredibly time-consuming and will-draining.
I mean, I'd go into the office fired up with enthusiasm for writing a chunk of Project X, and then find that I had to spend the morning running invoices and paying bills, the afternoon responding to emails, the evening doing tax and PAYE stuff, VAT, planning convention appearances, stock control, accounts, logistics... It's boring. It's very, very boring, and I've been doing it for eight years now. I have a list of project as long as my arm that I really want to create, or finish, and I don't have the time.
It wears you down. Many, many things about working in gaming wear you down. Fandom is a weird environment, populated by barely functional beings for whom gaming is their entire existence, and if a company takes over an existing game and doesn't publish stuff _exactly_ as the fans expect, you become their enemy for life. I'm thinking of one person in particular, who has posted reviews to RPG.net that contain deceptive factual errors about the products he's reviewing -- claiming one book was a third of its true length, for example. And he only ever reviews Hogshead products. You get a review like that, it's like a punch in the face. "I hate your company so much I am prepared to lie about your books to make you look bad." Great. I'm not going to miss that.