But what WOULD be considered a "new version"? I get what you're saying, but it seems unrealistic to me. If we take the example of let's say Adobe Photoshop, it's gone from about v5 through v7 then "CS1" (=8) through "CS6" (=13) or whatever it's on now, since I've been familiar with it (in about 13 years). That's roughly v5-v13, or 8 in 13 years, so one every year or two. (Plus many subversions including some semi-important ".5" updates.)
To me, that's how I judge a "version" of a program:
1) there's the rate factor-- it's about a year or more between versions, nothing crazy like Firefox. But not something like 10 years.
2) there's the compatibility factor-- the newer versions aren't backwards compatible and often require updating for new features. True for the iPhone (some apps) and Photoshop, but not for Firefox (at least not much).
3) there's the impact factor-- generally they seem like updates. However, the changes aren't hugely substantial as if you're buying a completely redesigned program. For Photoshop, the change from 7 to CS1 was major because it changed some aspects significantly; it was like a whole new product, perhaps entirely rewritten. But the other versions can still be "versions" I think. For example, you must pay again to get an upgrade but not when it's a minor version (maybe also you would pay for a .5 upgrade sometimes).
On the other hand, I find the version numbers for OSX-- they just want to call it all "10" so they pretend they're not OS11 and OS12, but they really are. (I could also rant/ramble about how they name them after stranger and stranger cats... but that's off topic... )