This is not true. Each version of Xcode works with simulator runtimes of the most recent two major iOS versions only.

Also, no simruntime for 7.0 and before works in El Capitan, regardless of Xcode version.

Although in all honestly, it's much less of a problem. Only about 6% uses an iOS version before iOS 8 at the moment. (I'm one of 'm!)

Interestingly, by doing this developers have a harder time supporting me (iOS 6 and 7 on phone/tablet). The result is forgoing app updates and even new apps altogether that I can't download. This pushes me to upgrade, and keeps the iOS adoption rate quite high. Facilitating devs in supporting old iOS versions does the opposite. I'm not a fan of this but I can easily imagine the benefits for Apple.

You're right, it only goes back to iOS 8.1, but you do get the devices for all current iPhone, iPad, Apple TV and watchOS.

Of course having a real device is much better, but as a web developer, this helped me pick up a Safari only bug very easily without needing to spend on a real device.

You can use OSX's debugger in Safari to remote debug a web page in the simulator, which I think is pretty neat.

I thought you could download old versions. They just don't come installed by default. Xcode -> Preferences -> Downloads.

Looks like you can, but only back as far as iOS 8.1

Ah, that makes the parent complaint make more sense then for sure. Thanks for checking (been a while since I used xcode).