Being a monopolist isn't all it's cracked up to be. Produce a durable good, and you're functionally competing against yourself.
For a Durable Goods Producer with Market Power:
Problem 1: durable goods can be re-sold. If re-sale purchases are cheap and reliable, why buy new?
Problem 2: after selling at high price, the firm wants to reduce price to get more customers. So, if you're a customer, you shound wait for the lower price to purchase... If you're the firm, how can you ever manage to sell at the high price?
Software is perhaps the ultimate in durable products. Once you have the program installed, it never wears out. Resale is prohibited by license agreements and made impractical by other technical means, but the second problem remains. How can software companies prevent consumers for holding out and demanding cheaper prices?
Big players in the software industry have found various ways to overcome this durable goods problem.
1) Bundling. Most famously, Microsoft got its big start by combining the Windows operating system with IBM machines. While the software may be durable, the computer most definitely is not. Replacement of consumer products guarantees repeat customers for their OS. Waiting doesn't help the consumer, because they retailer they purchase from will have to get a copy of Windows regardless.
2) Ongoing payment schemes. Subscription fees, downloadable content, and micro-payments have been used successfully by companies from Blizzard to Zynga. In addition to providing a check against piracy, each of these pricing methods ensure the up-front cost is only a small part of what the consumer pays for that software. Holding out for a lower price on the base product doesn't exempt someone from paying for the extras.
3) Build price discounts into the sales model. Some video game marketing tools (I'm thinking of Steam, from Valve software) build semi-frequent sales into their distribution channel. Users can buy a new game when it comes out at full price; wait a few months for the game to go on sale at 33% or 50% off; or wait several years to get it at deep discount. The amount paid depends on the gamer's urgency in wanting the game. It's temporal price discrimination which separates out high- and low-demanding users.
Software companies still end up competing against themselves to some degree, but with these sorts of pricing mechanics they're able to keep revenue higher than it would be otherwise.