Why is the article writer surprised
Also OS 9 and earlier are almost unrelated to OSX.
Apple's solution has always been for the faithful to buy a new Shiny and new programs. Though they have had compatibility tools in the past, maybe to run Power PC or OS9 stuff on x86-32 OSX, I forget.
It would be nice if I could run MacOSX x86 old 32 (which doesn't run on current OSX) and Mac OSX x64 on a VM on Linux, or any HW not supplied by Apple. But I'd be surprised.
I've an Android phone older than an iPhone 4s, it can USB load old apps and even install some from the Playstore. The iPhone 4s can only have music added by iTunes and nothing else. The previous owner hadn't added any apps, so it's useless compared to much older Android phones or tablets or PCs.