My best guess is that programmers build with the latest libraries, and the latest libraries require the latest OS version. If the dev is running on the latest version, it never crosses his mind to do otherwise.
My best guess is that programmers build with the latest libraries, and the latest libraries require the latest OS version. If the dev is running on the latest version, it never crosses his mind to do otherwise.
But there were just too many pieces of software that wouldn't run, and unpatched security holes didn't seem like a good idea either.
To add insult to injury, Apple doesn't allow you to virtualize non-server versions of 10.6. You can, thankfully, hack VMWare Workstation and keep running your previous machine's image that way, but it's shitty that you have to jump through those hoops. It seems geared specifically towards keeping people from continuing to use their old apps.
New and/or updated frameworks/APIs [1] make the developer's job easier. Why wouldn't you want to take advantage of them?
[1] https://developer.apple.com/library/mac/releasenotes/MacOSX/...