I'm sure AM books are listed on multiple retailers' websites--getting your book listed on a retailer's website is extremely easy--but it's very unlikely you'd ever find an AM book on an actual bookshop shelf (and if you did, likely it was the author who begged the bookshop manager to put it there). Companies like AM have very, very limited distribution--they have the kind that makes books available online, but not the kind that gets books into physical shops.
They also don't do any meaningful publicity or marketing, so any promotion is entirely up to the author. Basically, it's exactly like self-publishing, except it costs a fortune and you're sold a line of crap about what they can and will do for you.
I read Balzer's article, which I hadn't seen before. I don't want to get into a big argument, but he's really off the beam on a number of things. He's not talking about net royalties at all (the publisher's net income--list price less discounts and channel fees), he's talking about net profit royalties (the publisher's net income less production and sometimes other costs). That's a whole different animal. He also assumes "gross" royalties for ebooks will be no higher than 15%, while most independent epublishers pay 30% or even more; and he assumes that most sales will be print, which I suspect isn't true for most digital small presses.
Net profit royalties are a sleazy way for amateur or exploitive publishers to make authors think they're partners ("shared risk") while paying them the absolute least amount they can. It's not the author's job to assume the publisher's risk, or the author's duty to accept less pay in order to keep the publisher afloat.
- Victoria