Because Lion will be tied to a particular iTunes account, that should prove to be an effective "limit" on any attempts at mass copying.
Just to correct the record, Apple didn't take "a bath" at all on Snow Leopard, quite the opposite. As the company predicted, the low price spurred sales and deterred piracy, making Snow Leopard the most-quickly-adopted and top-selling version of Mac OS in the company's history, and helped to reinforce the various other incentives that encouraged switchers and fence-sitters to give it a try.
Lion and Snow Leopard both build mostly on top of the work done in Tiger and Leopard, meaning development costs of the OS probably weren't as high as, say, Panther or Tiger. The combination of the increase in the userbase needing to upgrade (which introduces a greater volume of sales) plus a lowered cost of development has resulted in a re-pricing that gives consumers a great break on price while still remaining reasonably profitable for the company.
As schweb said, the decision was made that the OS, like the iTunes Store, doesn't need to be a "cash cow" the way it does for Microsoft -- it seeds many other more-profitable areas.
). I'm excited for one or two features, so if the OS were to cost $129 like Leopard did, I'd probably hold off. But for $30 (free in my case) I'll have no problem upgrading.
