Ezra Gottheil, an analyst with Technology Business Research, downplayed the price cut, saying that the drop in revenue would be miniscule in relation to Apple's billions in revenue each quarter, and questioning whether the $10 off would prompt more people to upgrade than would have otherwise.

"I think [the price cut] changes almost nothing," Gottheil said. "It's not going to make a lot of difference in how many upgrade. Last year's [$30 for] Lion wasn't any large barrier to adoption."

In fact, Apple's Federighi touted the quick climb in Lion's share of the Mac installed base, repeating a past claim by Apple that it was adopted faster by OS X users than Windows 7 has been by Microsoft's customers.

According to Web measurement firm Net Applications, Lion accounted for about 44% of all copies of OS X that powered Macs which were online last month. Since the beginning of 2012, Lion's share has climbed 12 percentage points.

Because of the impending release of Mountain Lion, it's quite possible that Lion will peak this month. If Lion gains share at the average tempo of the last six months, it will climb to just over 46% of all Macs by the end of June, then begin a gradual slide as users migrate to Mountain Lion.