You could turn this into a book business. List books for sale that you don't own and this other publisher does own. Reduce the price over time until it is super cheap. Buy while it is low and resell it without the competition.
It is left as an exercise for the reader to show how to determine whether the other publisher actually does have a copy, or is indulging in similar behaviour.
This reminds me of a similarly unethical behaviour I've encountered recently: I tried to buy a certain rare electronics component, and found it listed by a bunch of people. There were lots of bait-and-switchers in the Google results, who only had the part listed for the googlebot to pick up, but as soon as I actually tried to order the part, their site told me they didn't actually have it and suggested I buy something else from them.
It gets worse: When I finally did find a seller who allowed me to order the part, they accepted my order -- and then came back later saying that, oh no, actually they didn't have it either, but would I like to convert my order into an order for something else? (Fuck off.)
My wife has experimented with that, sort of. She wouldn't not try to force the market down, but she'd occasionally find arbitrage situations on Amazon and exploit them. Buy a book placed at far too low of a price and then simply re-list it at a correct price.
The thing is that while these automatic pricing scripts exist, they aren't in enough widespread use to do what you're suggesting.
That's unethical business behaviour - it a microcosm of monopolies: buy up all the supply, then sell at a higher price than the previously going rate. It's common in business, obviously, but it's still unethical.
Not to mention that in order to make money over normal practices, you have to a) find books that are being sold at less than wholesale price (~60%ish RRP), and b) find a book that no-one wants to buy at your competitor's super-cheap rate that they will buy at your more expensive one - you're going to have to be in for the long haul to do this.
I don't think this strategy is unethical; it is really risky... probably so risky that it's naive for the long term.
It's not unethical because the buyer in this case can't really buy up all of the supply and therefore is just looking for arbitrage opportunities or opportunities to exploit weaknesses in a competitors business model.
The opportunities, over time, are very limited though:
1) You can't actually buy up all of the supply. If you were able to buy all of the listed supply and then reset the price you'd soon attract other sellers who had previously unlisted supply.
2) If there was real demand for an extremely high priced book I'd guess the author or publisher would be releasing a new version to meet the demand.
3) Although some printing of books are considered to be collectible, that market is limited. Generally the value of the book is the information it provides, which means that as the price rises the (perhaps less informative) substitutes become more appealing to buyers.
4) If you exploit a competitor's pricing algorithm enough to make them notice, they'll just change their algorithm. In this case, perhaps they don't sell you the books or they don't respond to your prices.
You might be able to make a few bucks on this strategy, maybe a few people could even eke out a living, but it would be risky... they'd earn it.
Not really that risky. If it was a naked call like in markets, then it would be really risky, but in this case you risk very little since there is no contractual obligation to send the actual book if you can't get it. You can reimburse and call it a day.
The calculations would have to consider the probability of not getting the book under the price of sale, the probability of not getting it over price of sale (investing the difference in avoiding a bad rating), and the chance that you won't receive a bad rating just for reimbursing it under whatever excuse. You can also ponder taking a bad rate eventually.
In other markets you'd have to basically get the book at any cost, which would make it really risky.
And in fact, in used book "arbitrage", the seller always has a very, very good excuse, which is that s/he "sold the book already" to someone in s/her imaginary brick-and-mortar store.
I was mostly joking but if you were really going to do this you'd have to develop strategies to reduce the chances of this happening and mitigate it when it does.
Maybe if you have a slightly bad reputation on Amazon that will keep people from buying your book. Maybe you can purchase the book locally and send it to the buyer in a pinch. Maybe you can purchase the book from the actual seller and just use the buyer's shipping address. Etc.