I could be very wrong but it was under the impression that once you buy something you own it. Since you've already bought 10.5, you own it. Downloading something you own shouldn't be illegal. Apple already has your money. Go to pirate bay and grab a copy.
Not quite.
If you went to a store and purchased a boxed copy of 10.5 when it was brand new, here is what you got, in the manner you have it:
1. You own, and can physically do whatever you want with, the box and everything in it. You can sell the disc to another person, you can microwave it, you can use it as a coaster, you can even put it in a computer.
2. You receive a
LICENSE to use the software that is included on the disc. To use said software, you must agree to the terms of this license. Among the items in the license is that you are granted the right to "...install, use, and run..." one (or 5 if you bought the family pack,) copy on a single Apple-labeled computer. ("Apple-labeled" has a legal meaning - slapping a sticker on a Dell does not qualify it.) This license also has the rather damning statement:
You may not and you agree not to, or to enable others to, copy (except as expressly permitted by this License), decompile, reverse engineer, disassemble, attempt to derive the source code of, decrypt, modify, or create derivative works of the Apple Software
The terms of the license specifically exclude placing the software for download on a website. And they forbid you from downloading it. So by having a legal license, and having agreed to the terms of the legal license, you are forbidden from simply downloading a new copy.
Ah, isn't United States contract law grand? While you have a legal license to run the software, to acquire a copy other than via Apple would be a violation of said license.
The latest version of a Mac OS Apple has released as a free download on their website is Mac OS 9.2.2, via the
NetBoot disk image. Prior to that, the latest version available free from Apple as an installer to install on a machine was Mac OS 7.5.3, which seem to have gotten lost in a website reorganization.
No version of OS X prior to Mavericks was ever "free for download", although 10.1 was available for free on disc to 10.0 purchasers. (You did have to already have 10.0; if your computer only came with Mac OS 9 or earlier, and not 10.0, you still had to pay for 10.1.)