hayesk said:
Upgrade is derived from "up" and "grade", meaning you are going to a better (up) grade than what you had before. i.e. It only means you have a newer version than what you had before. It does not mean you need to install it over existing code. It's just happens to be that way with other software products.
It costs $129 to get the latest version of MacOS - for everyone. Everyone has a previous version, therefore they are upgrading to the latest version. Not really a difficult concept if you separate it from the actual install code.
seafox was right.
apple's os price model is the same as most every other commercial software model used in the past number of decades. with those, you pay some extraordinary price for the initial package, and any smaller additions to it, also known as
upgrades, cost a fraction of that base price. sometimes a credit is given to those with just-barely-out-of-date versions of the same package.
with os x, $129 is the price of the initial package, and any further point-point releases are both
downloadable and free. it's only fair seeing as how most of them are for maintenance and don't add entirely new functionality to the system, but they do in my opinion qualify as upgrades as much as patches. all people see however is $129 repeated over and over, not thinking about the work apple programmers put into it the rest of the year. you should be glad we're not talking about sgi boxes here.
can you
upgrade 10.1.5 with a 10.2.8 installer? of course not. there's a large enough gap between 10.1 and 10.2 to qualify the latter as an entirely separate package. apple has long since abandoned their version seven and eight era "half-way" releases, 8.5 and so forth, which naturally costed less due to their nature. also, i don't see the point of a credit system for owners of previous packages because each new mac comes with some version already. nobody would have reason to pay full price because everyone would qualify for a credit.
with that said, i do think the current annual charge is a bit steep. all apple should do is decrease this, not throw a wrench in the model. $75 to $99 seems more reasonable to me. if i recall, os 8 was $99.